you don't need a dish, you do need a legitimate Dish Receiver to be a Dish Subscriber though, so just buy a no contract receiver. Lie, tell the customer service person you self installed the dish and the signal is fine, and give them receiver and smart card numbers.
Or if you wanted to, you could install the dish... but if $22 sounds like a fair price for ONLY HBOGO to you, you don't have to. My friend didn't.