Do we have to pay electricity costs if we purchase? If so What is the combined wattage of the miners?
I am very interested

Heh, no my prices include electricity. I'm paying very cheap Washington hydro prices. Honestly I should probably shut down the Rockminer T1 but I've underclocked it to reduce it's wattage and it's doing ok.
Whole thing draws a little under 2KW. I don't make much on this rental tbh, I'm offering this more for the fun of keeping the stuff running and a little money on the side without the stress of watching bitcoin 24/7 for the next price jump.

One thing everyone should know though: This is a rural location with reasonably reliable electric (mostly underground wiring here), but it's still not battery/generator backed. If electricity goes out though, I'll arrange a usage extension in the contract.