Car dealer will take cash for a car, just ask them. They don’t care about “drug dealer” or any such nonsense. They are in business to sell autos. If you go to your bank and have $26000 in there and say “I’m going to buy a car with this money, what do I need to do?” they will help you do a wire transfer or a certified check to the auto dealer. The auto dealer also will work with you to get paid. Cars are paid for in cash every day. If you come up with a miracle giant wad of $5 bills yeah, they will probably think you are up to something. But it is just a car, and if you save your money you can buy whatever you want. And when did you last use your CREDIT CARD to buy a car?
It does not matter. ANY cash transaction over $10,000 must be reported to the FEDs.