i am new to sat. my pre-home owner left me one directv dish. all cable connected. he said what i need is just a receiver. i went to eBay for a check. found that i still need to have a access card with the receiver.i know with the card, you can view some kind of channels, but i don't know why they sell these cards so expensive. i assume they are selling pirate cards,but after i asked one seller, he said i still need to do subscibe with directv. i am confused here. does anyone has experience in using directv?what is P4 card? and how does it works?