Trade in offer fair?

Im just curious what people think about a recent offer i was given at a local game store. I had 3 psp games cib. Dead head fred, Tactics Ogre, and Smack down vs raw 2010. I know these aren't heavy hitters 9r anything but he offered me 15 cash and 20 credit. Honestly I was expecting to get around that just for dead head fred cib.