Trade for What You Need
You may have heard of people hosting clothing swap parties. Well you can do the same for your baby gear. Just think of all the "necessities" a parent needs to get ready for a new baby: newborn clothes, a car seat, a bouncy chair, a bassinet, bibs, booties, blankets, hats, slings, wraps, diapers, and so much more. Once the newborn phase is over with larger clothing is needed, along with outerwear for the season, toys, books, shoes, a highchair - the list goes on!
These necessary items are used for such a short time before your child reaches their next new phase. Most baby items are in excellent used condition and have a lot of life left in them when you are done. Sure, you could take them to a consignment store or donate them to a thrift store, but your extra outgrown baby gear is perfect for bartering and trading with your friends.
By trading baby gear instead of buying new, you and your friends will save so much more than money. You'll also eliminate the packaging waste and fossil fuel emissions associated with making and transporting new goods. Everyone wins!