I agree that Auto Engenuity is the best bang for your buck.....but if you want a stand alone scanner i would go with a Matco/OTC scanner over a snap on one myself. I have played with most of them and they by far seem to be the best deal as far as overall functionality....
The other thing to consider would be finding a used snap on brick. Snap on is not going to support them after 08 if i remember right....so a lot of people are selling them. If you got one with current software you could have something that would work for your truck pretty reasonably.....downside is they wont be updatable soon....