Selling Previously Purchased Items on eBay/Mercari/Etc.

[MartinR59]

Hello - I currently sell previously purchased items on multiple platforms (eBay, Mercari, etc.). I don't go out and purchase these items with the purpose to sell however. These are old clothes that my kids have outgrown, or items that I just no longer need anymore. For example, I will sell a shirt that I purchased years ago for $10, for $2 plus shipping. I believe eBay will now be sending 1099's to everyone, regardless if you "profit." How would I show this on my taxes, that while I did sell on eBay, I did not make a profit. 

Thank you so much!

[MartinR59]

Also, if I previously paid tax on each item, do I need to pay taxes on it again when I sell, for less than what I paid for? Should I track each individual item on a spreadsheet with the purchase cost and resell cost?