Joined as E-3 at age 27. Started from scratch because I'm an immigrant. I assume you get BAH. Military pay including BAH isn't great but it's not bad either. I think the easiest key to success is not spending too much. I don't have a car payment but I do own 2 cars for myself and my wife. I bought those for cheap but they are reliable. I don't spend money on housing because I live on post, I know I can save more money if I but a house or live off post but I'm satisfied because there's not much hassle living on post. So I don't have any monthly payment except phone bills and internet service, that helped me saving $40,000 in 3.5 years. There will be $27,000 bonus kicking in later this year so I'm happy with military life.
Don't spend TOO much on something that doesn't worth! You can still have fun. I think that's my 2 cents.