Yes, you need to report the $10 as income.
When you receive a cash rebate on an item, that isn’t considered income; however, you have to reduce your basis by the amount of the rebate.
So, when you purchased your item for $25, then got the $25 rebate, your basis was zero.
Your profit was your sales price ($10) minus your basis ($0).
Please see Cash rebates under Other Income in Publication 525 (2021), Taxable and Nontaxable Income for more information.
TurboTax’s Cost Basis: Tracking Your Tax Basis - TurboTax Tax Tips & Videos is also very helpful.
