Kids grow up so fast, don’t they? One moment they’re a tiny body in your arms, and the next, they’re walking, taking toddlers, who’ve outgrown their clothes, their shoes, and their strollers. If you’re a parent or expecting, you probably know that buying new baby gear doesn’t come cheap—and costs can add up when you have to replace them every time your child goes through a growth spurt. The best way save money on baby products, like clothes, shoes, and other essential items both big and small is to buy them secondhand. Used baby gear is a great (and safe) option if you’re on a budget—and who isn’t!

There’s a robust online marketplace of secondhand baby gear, and you’re likely to find whatever your growing baby might need through any one of the options available. According to Jean Moorjani, MD, a pediatrician at the Orlando Health Arnold Palmer Hospital for Children, purchasing used baby gear won’t just save you money, it’s also more environmentally friendly. “If we are able to get things secondhand, then that’s a good way to give a second life to something instead of throwing it away,” she says. Reducing waste is a sustainable win-win for both you and the planet.

How to shop safely for used baby gear online

For all the benefits that buying secondhand baby gear can afford parents, there are important things to keep in mind before making a purchase for your little one, with safety being the number one priority.

1. Look out for wear and tear and any safety hazards“Anytime you buy anything secondhand, you want to make sure that everything looks like it’s in good shape,” says Dr. Moorjani. Avoid purchasing used baby items that have been damaged, developed mold, have missing or loose parts, sharp edges, or chipped or peeling paint—which can all pose a safety hazard. You’ll also want to inspect the product for anything that can cause a choking or strangulation hazard, looking out for cords or small parts that your baby could potentially ingest.

2. Ensure items come with an instruction manualIf you’re shopping for used baby items that require installation (think: high chairs, strollers, and playpens), you’ll also want to ensure that it comes with an instruction manual. “The instruction manual has the correct instructions on how to install [an item] properly and safely,” says Dr. Moorjani.

3. Check for product recallsYou’ll also want to check for product recalls—which is when an item has been found to have defects or safety issues. She says that you can typically find this information on reputable consumer websites, like the Consumer Product Safety Commission website, cpsc.gov, or recalls.gov.

4. Purchase from a website or app that offers returnsAnother thing to keep in mind when shopping online for secondhand baby gear? “Look at the return policy” before committing to a purchase, says Dr. Moorjani, “because if something arrives and you’re concerned that the product isn’t safe, you want to make sure you can send it back for a refund.”

5. Keep your pediatrician in the loopWhen in doubt, ask your pediatrician if you’re unsure about whether a product is safe to buy for your baby or not. “A pediatrician is a good source of information so don’t forget about them,” says Dr. Moorjani. “We’re available to answer any questions about your baby and provide advice.”

Baby gear to avoid buying secondhand

Clothing, shoes, toys, high chairs, strollers, and infant bathtubs can all be purchased secondhand for as long as they’re in good shape and pose no safety risk. However, there are certain items that you’ll always want to buy new, says Dr. Moorjani.

“Cribs are definitely a no-no,” she says. “Today, there’s more regulations when it comes to crib building and crib safety, so you don’t want an old crib.” Another thing that you should always buy new? Car seats. “Car seats technically expire after several years,” says Dr. Moorjani. “You don’t know the history of a car seat if you’re buying from a secondhand store. And if it was involved in a car crash, whether minor or major, then it shouldn’t be used at all.”

The best sites and apps to buy (or sell) used baby gear

With all this in mind, take a scroll through these secondhand baby sites and apps to find clothing, toys, gear, and more for your little one—or even consider selling items they’ve outgrown to parent who might need it.

1. Kidizen

Kidizen is a website and app for parents to buy or sell secondhand baby clothing, shoes, accessories, and toys. You can quickly navigate their selection by category, with one even dedicated to mothers. Kidizen vendors must adhere to a list of “house rules,” ensuring that the condition of items being sold are clearly communicated and all defects are clearly stated in the description. Otherwise, buyers can request for a full refund on the item they purchased.

Parents interested in joining Kidizen as sellers have the option to list products themselves or work with a Style Scout. Scouts provide a white-glove consignment service, which includes a consultation and at-home pickup services, making it ideal for busy parents. Kidizen deducts a 12 percent marketplace fee for every item sold through their platform and sellers are responsible for shipping costs.

2. GoodBuy Gear

GoodBuy Gear is an online marketplace where parents can find everything their child might need (with the exception of a wide range of secondhand baby clothing). Products on the site are inspected for safety and quality assurance so what you’re buying is almost, if not just as good as new. If you aren’t satisfied with an item, they also offer a 14-day return policy.

Looking to declutter your home of used baby items? Selling on GoodBuy Gear is made easy, too. Just schedule an at-home pickup or bring used baby items to one of their drop-off locations—they’ll take care of the rest, from snapping photos of items to cleaning them to listing them on the website. For every item sold, sellers can receive up to 85 percent of the sale value.

3. Kidsy

Kidsy is a website where there’s everything from secondhand baby clothing to shoes and accessories for sale. They also have a variety of toys, books, travel gear, and nursery items. Whatever you’re in the market for, you can expect to find items that are up to 90 percent off their original retail price. And if you receive an item that wasn’t in the condition it was described, Kidsy also offers returns within 48 hours of delivery.

On Kidsy, parents can also sell baby gear their children have outgrown. Sellers will be responsible for uploading items to the site, with photos and an accurate description. If a purchase is made, sellers will also have to ship the items to the buyer themselves. Kidsy will take a 5 percent commission for every item sold, regardless of its sale price.

4. Markid

Markid is a website and app that serves as a one-stop shop for parents looking to buy secondhand baby gear, clothing, and shoes. Buyers purchase directly from sellers, and to ensure that every product on the platform is in good condition, sellers are required to take clear photos and provide detailed information. In the event a product isn’t up to standard, buyers can request a refund within 48 hours of delivery.

If you want to sell used baby items, signing up on Markid is free. Once you receive a purchase on an item, you have the option of meeting up with a buyer if they live in your community or delivering it to their doorstep by mail. Just keep in mind that you’ll be responsible for the shipping costs, and Markid charges a 10 percent selling fee based on the listed price of an item.

5. Rebelstork

Rebelstork is a website for high-end baby gear, with the mission to make “parenting lighter” on the environment. They sell overstock, open-box, and resold items, and each item is vetted for safety by Rebelstork employees before it is made available on their site. Any items that are inauthentic, have incorrect or missing parts, or don’t match their description can be returned for a full refund within 24 hours of the item’s delivery.

Rebelstork also takes items from parents looking to sell old baby gear. They have at-home pickup services for sellers, as well as convenient drop-off locations. Currently, they only service from the Greater Toronto and the Metro New York area, but they are looking to expand in the future. Sellers can receive up to 80 percent of the sale price, depending on the item’s value.

6. Stork Exchange

Stork Exchange is a website where parents can find secondhand baby gear, like carriers, diaper bags, swaddles, and a variety of baby toys. Every item on the website is subjected to inspection and a thorough cleaning prior to being listed on the site. They also have a 14-day window for returns if a product is received broken, defective, or just doesn’t meet the buyer’s expectations.

Currently, Stork Exchange isn’t accepting used baby items from people interested in selling on their site, but you can follow them on their social media channels or sign up for their weekly newsletter for updates.

7. Toycycle

Toycycle is a website that offers secondhand baby clothing, toys, and big-ticket items, like high chairs and strollers. Each item listed on their website undergoes a rigorous vetting process and is inspecting for cleanliness and safety, so parents can shop with peace of mind. If a purchase proves to be defective or doesn’t match the description, they offer full refunds, too.

Those who want to sell their child’s old items can also list them on Toycycle. You can schedule curbside pickup in San Francisco, but if you don’t live in the Bay Area, you can use their Cleanout Box option, which lets you ship items from anywhere in the continental U.S., or the Stuff & Send Bag, which is available nationwide. Toycycle will take a percentage of sales made, which varies according to the value of the item sold.