That's exactly what I was suggesting. Unfortunately, they've been pretty adamant that HBO GO require a cable subscription in the US. In parts of Europe it is available for purchase as a standalone service, but it is very expensive (more than twice as much as Netflix) and requires three month termination (so even if you don't like it after the first month, you have to pay for another three after you cancel). I believe that someone said that the equivalent cost of canceling after the first month is still $97 US.