Usually, ceiling paint is very reasonably priced.
Primer will look ok, but it may actually not cover as well as regular paint. Primer seals and provides a good bonding surface but it's not the same as regular paint. You should be able to get a gallon of ceiling paint for 10-15 bucks
Good luck with the tape. Be careful when you take it off. Pulling straight out on tape can tear the paint right off of the wall. Double it back over itself and pull steadily right against the wall.
For the best results, Prime and then paint. The new Drywall compound will absorb paint at a fast rate. The primer will seal it all and help hide the different surface textures.