primer vs paint

once i finish fillin fender flare holes, molding in a roll pan, and all the body work on my bed, i am stuck between to choices... paint on about 3-4coats of prumer and drive around with a primer bed, which i haev no problem with, cept i have been told by a couple of shops that water will absorb into the primer and the metal will rust over a period of 3-6months.

is there any primer that will withstand the elements of the texas heat and occasional rain storms, and when the time comes to paint, just scotch brite the bed clean it and spray some paint without haveing any problems?

im ready to have my truck one color, but cant afford a complete painjob right now, so thats why i am considering the primer paint job..if i got a semigloss primer(if ther is such a thing?) and once it was sprayed and cured, spray a coat of clear on it to seal it up, would that work?and where can i get a white semi-gloss primer? if there is such a thing?thanks

If your willing to put a clear on it why not just paint it with a flat or semi-flat paint? I think the primer might get discolored under the clear and not give you the look you want. I'm using Krylon semi-flat black paint on mine until I can paint it and I like the way it looks. Primer does absorb moisture, and it might work in California but not in Texas.