Jack is right, airless spray shouldn't be used in an occupied home, especially by a novice. Outside...yes, inside....no. Please don't take offense to my remarks. If the sprayer is used incorrectly it can be very dangerous. The time spent setting it up and cleaning it up will most definitely cancel any time saved by rolling the walls and ceilings. Furthermore can you justify spending at least $700 to save (?) some time? Oh sure the big box stores sell the sprayers cheaper then $700, but you asked for a sprayer best for spraying walls not for a one time use. Give it some thought. Take the money for a decent sprayer and spend it on primer, good brushes and a good quality finish. Better paint will save you time, cheap paint only costs you time and money.