Finding the right sound card to my recivier?

ok.. i am trying to hook up my pc to my tv to watch movies... for video i have DVI to my tv..no problem.. but DVI doesn't do sound..so i'm looking the cheapest option of a sound blaster card i need to get my sound to my Receiver.. i think i need a card that has a digital out..i've ever seen one that has an optical that's cheap.. hellpppppp