Papa Murphys will cost a bit more than Costco or the supermarkets unless you have a super coupon. The good thing about them is that you can choose toppings. I'm fine with a Supreme mix, but given the choice, I'd rather have sausage, mushrooms and olives or onions. Other than that, I think both are fine and beat the hell out of any of the nation chains. All of their sauces taste like flavored ketchup to me.
Good Luck!
Ric at Joes