2k urethane or epoxy primer?

So ,excuse me for being frugal but could I use a spray can of epoxy primer over the bare metal for adhesion and then buy a gallon of urethane to spray the whole car,? Hate to buy 2 gallons of primer.
Ah man i don't mean to sound like a know it all but i have been doing it since
the late 70's LOL, And yes Dominion sure seal sell a spaybomb of self etching which you can use as a base coat in small areas before prime.
:burnout: