Diaper Rash

Ok so I think my son has diaper rash...I keep reading all these things that say change them right away. I understand that and I'll do what I need to do to help my son, but...seriously? That means like 15-20 diapers a day. And those things aren't cheap. Plus WAKING HIM UP TO CHANGE HIM...and he only sleeps like an hour and a half at a time already :( sometimes two hours. I feel so frustrated (mostly because I'm overtired, I'm sure). Don't know why I'm posting this. Just venting I guess.