How much money will I have made in my 4 years active duty in the Air Force?

i'm leaving for BMT in February for the Air Force. I'm going enlisted and signed up for four years and Ive been trying to figure out about how much I'd be making. I have 22 college credits under my belt, so I've been told I can go in as an E2, opposed to an E1. If I were to not spend a penny from when I go into the Air Force to the end of my 4 year contract, about how much will I have made (this after they take out for taxes and uming I don't get into any trouble while I'm in there, hopefully becoming an E4 toward the end of the 4 years) I've looked at the military pay chart, but want someone with experience because I don't exactly know how I will go up in rank since I'm going in as an E2. Also is it possible for me to become an E5 in 4 years? If so, how likely? Any info greatly appreciated.