What would it cost to do about 10 loads with drying?

Wesley is right. It depends on how big the loads are - do you have big blankets or need to sort colors, whites & such into small loads?

I use the big one for $6 and I can normally do both my son's and mine laundry in 1 or 2 of those

Washing machines are $2, $4, or $6 each according to size, small dryers are $0.25/5 mins and large dryers are $0.25/3 mins. Depends on how you wash really.