Well, I inventoried the parts I got today, and it turns out I had 1261 pieces in there! Yes, that's almost 200 more pieces than cents I spent! basically each piece came out to .86 cent! Granted, most of it is small pieces, but still - you'd spend between 5 to 25 cents for the pieces I got. For example, I got 244 1x1 transparent red tiles, which are $0.09 at the PaB page on the S@H website, but I got them for $0.0086 each!
Without the $5 credit, they're still just above $0.01/piece, so compared to S@H or briclink, it's a STEAL of a deal. Granted, you are subject to what they have available to you as opposed to having free reign pick, but there's plenty of useful pieces. Check out what I got in my Pick a Brick Inventory set at Flickr.
Just to whet your appetite, here's a pic of the bulk of what was in the cup. This wasn't everything, though, as I didn't have enough room on my desk to spread them all out!

Click on it to go to the pic in the stream - I notated each piece with the type, color and quantity. The next pic in the set is the rest, which was comprised of 1x1 cheese slopes and 1x1 round plates. There are also tips on how to maximize your fill in the notes on other pics.












