From your for-sale items in your listings showing a Florida location, I'm assuming you are also in Florida.
As a seller, you may not have collected and remitted (sent to a State) sales tax from your buyers, but now eBay does. eBay has been doing that since the very first online sales tax laws were activated several years ago.
As for paying sales tax in Florida, prior to July 1, 2021, Florida didn't have Marketplace online sales tax laws activated. You were not being charged by eBay for sales tax for on line purchases. As a resident of Florida, you were on the honor system to pay Use tax (the direct from the buyer version of sales tax) when you purchased items online but weren't charged sales tax by your seller. Now, the big online websites such as eBay are required to collect and remit sales tax to Florida on your online purchases.
