Yeah, had a similar experience here. Local shop was advertising on TV that if they couldn't beat competitor's price, I'd get the tires for free. When Toyota was having a buy 3 get 1 free special last November, I took them the quote and they said they can't get me the BFG's for that price without losing money. So I said, then do I get the tires for free since they couldn't match or beat? They stuttered a bit and said it only applies to tires in stock. Bunch of crock.
By the way, that is some awesome pricing on the BFG's. Around here, the Coopers are cheaper than BFG's, but nowhere close to what you got them for.