Selling on eBay for business, how do you account for inventories bought many years ago?

Let's say I''ve been regularly selling on eBay as a reseller and been reporting this business on Sch C. If I decide to sell bunch of items that I have bought several years ago that were originally meant for a personal use, how should I account for their cost basis? They were originally bought for a personal use, so their cost of goods was never entered into Sch C. But Sch C. only seems to be able to enter cost of goods bought in the most recent year(2024).  If I bought items back in 2015~2022 and sold for a profit, where can I enter the cost basis on Turbotax?

Thank you.