peter wrote:
The inside of my garage is not painted. It is mostly tan color from the
drywall. I want to brighten the garage by painting it white or off white.

What type of paint and sheen should I use? Can I do without a primer? I
don't mind if it doesn't look perfect. But I do want the paint to last as
long as possible.

Get the surfaces as decent as you want them first, tape & mud as you
prefer. Then paint with a regular drywall primer because 1) it's really
economical; 2) it looks fairly decent as applied ; if you decide it
should be more elegant later your primer is already in place for the
topcoat. We call that a win-win situation, right?

Joe