Lawn Rates

Ok, forget the whole 20 - 25 bucks a cut thing for a moment. I'm about to place some bids on commercial accounts. What numbers do ya'll use to base your bids on. The accounts are in the Dallas, Texas area. St. Augustine and Bermuda are the grass types, sometimes I'll run into Fescue, but that's very unlikely.

Mowing per/sq ft...
trimming linear feet,
edging...

I havent big on commercial accounts before, and I want to underbid some companies but I don't want to be doing these jobs for pocket change. Help is much appreciated Thanks guys.