Official Nintendo Players Guide
Top Secret NES
Top Secret Game Boy
Top Secret Super NES
How To Win At Nintendo
How to Win At NES #1
How to Win At NES #2
How to Win At NES #3
Gamepro's Video Game Bible
Nintendo Game Boy
Pocket Power (This was handed out at the movie, The Wizard).
Total: $10

On eBay I got:
The Legend of Zelda Tips and Tactics
Total: $8

I don't think that the Legend of Zelda Tips and Tactics is a stellar price (quite expensive) but I've been thinking of it as a lot of books for 18 and it helps lessen the sting. I'm especially excited about the Pocket Power. I've been looking for one of these.