About how copious gallons of paint for the inside of a 3,000 sq. ft. home? Just trying to get an hypothesis of what I'm looking at....

Just trying to get an hypothesis of what I'm looking at. Also, is there a paint sprayer you'd recommend? Does using rolls look a great deal better? The time difference in completing the undertaking btwn. the two? any hints for painting the indoor of a home?
Which path should my bed frontage?
Answers:    10..if you want the mission done right do it by hand..we are repainting our current house we moved in at the termination of jan..the walls look like crap and they be done by professionals..we do a much better job by mitt...
I'm decorate my home for the first time...
A gallon of paint will cover approx. 300 sq.ft to be on the safe side, plus you hold to figure the ceiling as well. If you already hold furniture in the house you are better stale to use a roller, less mess than a sprayer.
When I am fine art a whole house I travel thru and do all the ceiling first if I am using all white for the ceiling. Then start with one room and do adjectives the trim around base boards, widows and door frames as ably as around the ceiling, once that is done you are geared up to roll the whole room. Repeat for the rest of the rooms. Good luck.