What main street do you shop on? Because I gotta agree with the guy what with the gas station example, that's not how it works literally everywhere I shop.

When you bought at $419, did you buy knowing you'd need the additional $50 in hardware? I know it's pretty much pointless to argue on the internet because everyone is always right and always wrong simultaneously, but you gotta admit you did agree to buy them at the list price. It would be mighty friendly of Bitmain to make good to the people that bought at the exhorbitant price instead of the slightly less exhorbitant price, and apparently they feel they're doing so by offering coupons. That's technically more than they're required to do. The only thing they're required to do is ship you the stuff you ordered.

And remember the first rule of bitcoin - only invest money you're willing to lose.