Reversi & Chinese Checkers are both 99 cents, the rest of them are $4.99.
My kids have played the heck out of the ones we have bought - i don't regret buying them for $5. I figure it's cheaper than the DS's they wanted last Christmas.
Peggle for sure is worth the $5!
ETA: Actually, i wish i hadn't bought Lode Runner. I actually accidently clicked on it to buy, and it was the day my click wheel on my iPod Video broke, so i've never gotten to play it, and the kids have ZERO interest. Oh well......