How Much Paint Should I Get?
Add the lengths of each wall and multiply perimeter by total height of walls. Subtract the windows and door (Standard door - 20 square feet/Standard window - 15 square feet)
What type of paint should I use?
For Wood: Use satin on wood for a low luster finish.
For Ceilings: Flat
For Walls: Matte or flat
Matte and flat can be touched up without seeing the touch up due to oxidization.
Paints like egg shells can't be touched up. They require a coat to be applied to the entire surface and also require an additional coat to get their finish right.
Gloss also requires perfect walls: the shinier the paint, the more imperfections you see.