Maximize Vehicle Rebate

Hello. Later this year I’m going to be purchasing a hybrid vehicle. U.S. tax law offers a rebate of up to $7,500 bucks. Typically, I don’t owe much in taxes, which means I might get none of that rebate. I’m looking for ways to maximize that rebate. My first thought is capital gains tax? I could unload some stock and pay cash for the vehicle. I don’t know much else about taxes—H&R Block does the thinking for me, usually. Any thoughts?