After I ordered one online that was going to cost me $15 with shipping and handling (the shipping and handling were about twice as much as the fuel cap was), my dad found a used one at a salvage yard for $2.
Out of curiosity, I called the dealership. Guy said he had one, but “it wasn’t gonna be cheap.”
$33. For a bleeping piece of plastic.
So I told him that I had one on the way, and asked if he thought it was a big deal to wait a few more days. He said no. Dad put the new cap in the mail yesterday.
Hurrah.