They answered on the other post. Here was the response:
According to the IRS "If you sold an item you owned for personal use, such as a car, refrigerator, furniture, stereo, jewelry, or silverware, your gain is taxable as a capital gain. Report it as explained in the Instructions for Schedule D (Form 1040). You can't deduct a loss.
However, if you sold an item you held for investment, such as gold or silver bullion, coins, or gems, any gain is taxable as a capital gain and any loss is deductible as a capital loss." https://www.irs.gov/publications/p525
It sounds like you may purchase the items with the purpose of re-selling them. In this case this would be considered a business activity. You would then need to file a Schedule C with your personal tax return to report money you made or lost in your business.
In both instances your thrift store receipts are sufficient for reporting the cost of the items you sell.
For a business return you can just lump the income together. You can also lump like expenses together for each category of expenses for the year.
You can include the e-bay sales tax as an expense for your business.
Most businesses are run as a cash business meaning you would include the expenses and income in the year they are made. So in your Q4 you would include the expense in 2022 and the income in 2023.
