I was thinking along the same line as you Speedracer when I read the "you get what you paid for" statement. I see fake Mobil pump plates sell everyday for WAY too much money, and the buyers are not buying an original sign for $200, but a $25 repro.
I think the exception to the rule these days would be to underpay for a sign. About the only way that happens is when a seller lists it at a cheap BIN and actually honors selling it for that amount, even after the higher offers to buy the item flood in when it's posted here on Old Gas that someone got too good of a deal and others can't stand it!