Hi Julie
I'm not sure what the typical rates would be in your area but I'd guess the best thing to do is to check out the ads in the local paper. However, BE PREPARED, getting good reliable cleaning staff is a problem for every single contract cleaner I know! Once you get them do everything you can to keep them, even if you have to pay a little more.
I would suggest that if you have staff cleaning at a single premises for each shift then you would pay them from the time they got there until the time they leave. On the other hand, if they will be travelling from site to site in a single shift (if you were doing house cleans for example) then I would suggest that you would pay from the time they got to the first job until the finished the last one.
Hope this helps
Good luck