Awhile back, I bought a minivan and had to wait for the bank to mail me the check. It came in and went in to give the check and take the van.

Salesman told me they'd figured out the tax incorrectly (didn't take into account lower tax for active duty military) and asked for my check. Warning bell somewhere in the back of my brain went off and I sat and looked at that sales sheet for a good 10 minutes in silence. So long my wife started asking what's wrong- thought I was having a stroke.

I finally figured it out (hey, I'm not good at math). They reduced my tax by $500 but the check was preprinted for a specific amount which is exactly what was on the bottom line. I told the guy, you owe me $500 back. When I finally figured it out, he said "oh no, we put all-weather floor mats and mud flaps on the van" and surprisingly that came out to exactly a $500 value. I said I didn't ask for those things, take them out and give me the cash. he said they couldn't do that because the flaps were screwed in, so I said thanks for the lovely parting gifts and give me my $500. In the end they took out the floor mats, left the flap, and gave me my $500.