SW tank maintenence people wanted

i was just wondering about the maintence people for SW tanks do? would it be worth getting into? where i live in oklahoma there isnt but 2 lfs . but on graigslist there are people selling frags, fish, and setups. so i know there is people out here that could use help. i love this hobby and ill be going to school here in the next month and the extra money would help. would love to know what you people usally do on a call and or normal maintenence.