Per the IRS, cash rebates from a dealer or manufacturer for an item you buy generally not taxable. If you received a 1099-K, it reflects gross income received for this activity and needs to be reported since the IRS has received the document also.
You should enter the 1099-K in TurboTax (see below) and add a separate line item with a negative amount that represents the rebate and coupon income that is included on the 1099-K. You can essentially enter 2 line items in the ''Additional Income'' section, one as a positive number for the full amount and below it an offsetting negative amount for the total of the manufacturer incentives received. Image attached.
Here is how to enter your 1099-K. https://ttlc.intuit.com/replies/5108144
https://turbotax.intuit.com/tax-tips/irs-tax-return/video-are-cash-back-rewards-taxable-income/L1FWH...
