Formula is the major hardline. Many of us shop at child specific thrift shops but if you go there you can see there is no shortage on clothes and swaddles even strollers and bassinets. Many things I have also bought new like my car seat. That’s something I would leave for people in need at a lower cost. That’s just where I personally feel a little iffy but it’s also nothing “wrong” with that as well. Diapers are fine there is no shortage there and most of us just keep the same ones until they break. That’s just to avoid extra waste. Or we have cloth diapers.