Well heres a few codes for some free PSP comic books...
All Hail Megatron!!!!
Code: EC2N-9HBR-HJD6
Star Trek Year Four: The Enterprise Experiment #1
Code: 724K-A4BG-JLD7
Aleister Arcane #1
Code: 63N8-R2BF-9E4D
Astro Boy: Movie Adaptation #1
Code: FF3N-H7B6-M2JF
*note* These will be usable until December 16th if they dont work before then try redeming them from PSP store.