I am a member of this and I can tell you that the plan is very flawed. I purchased games on four different occasions last week from Best Buy and only one time did I get my discount and that was on an online purchase. I have a case open up with Best Buy about this but I am one immensely dissatisfied customer!
Why didn't you check the price when they rung you up in store? It's not very flawed, it only did not work instore.