I Need Help with PSA Grading - 1974 Topps set

[whosnotwo]

I collected cards when I was a kid (80's and early 90's) but haven't bought a pack of cards or looked at them in about 15 years. I recently came across a pretty nice collection at a yard sale and started searching on eBay for some completed listings. Everything that went for high dollar was graded by PSA or something else. I'm having trouble figuring out how to get these graded. Is the only way I can do it to send it to CA and pay $15/ card? That seems like a rip off. What if the card values less than $15? Can some one explain to me why this is? it seems like it has become a business more than hobby.

Anyway, I have another question. What do I do if I want to get a whole set graded? Is it the same process, but I have to pay for each card? At the yard sale, I got a 500 ct vending box of 1974 Topps. The cards are in pristine condition. I think I may have something very valuble here and I want to get the most out of them.

Thanks for the help.