How much does it cost to have a pool maintenance guy clean your pool?

Question:On average how much do they charge to clean an average size inground pool? Also how often should they clean it? Im asking out of curiosity because my uncles thinking about purchasing a house with a pool and would rather have someone do it professionally and know the facts before purchasing one.

Answers:
It is a monthly process, and usually runs in the $75.00 per mth range.