sha256 contracts are lifetime yes. i think the "fee" is $0.0028 per Gh per day.
but if you use calculator, just put power cost to 0 just cause its way easier to see. but you could calculate power usage separate if you wanted. i just know from personal experience, cloud mining is WAY easier. i have miners, some burnt out. some are too expensive now to run, some are too hot to run, like heats my whole house lol. but i do have a few efficient LTC miners i run :D other than that im HEAVILY invested in genesis :D like over $1000 lol