I am building this PC and recently...the price on everything skyrocketed. I need to find a good power supply for it, I thought 500W would suffice, but I've been told that If I ever plan on Crossfire, I need 700W+. Do I really need it? What inexpensive power supply can I buy without sacrificing quality? ~Here's what I have. I have already had shipped case, mobo, and disk reader.