You can use quality rattle can primer but keep in mind it breaths. Top coat with paint ASAP. Napa carries some quality rattle can primers, they are $7.00 or more. If the parts are being blasted the media should remove any rust. 99% of a good paint job is preparation, a clean surface. Make sure you use a pre cleaner (lacquer thinner is ok) before applying any primer. Gun wash is same product and cheaper (lets keep within your budget) but likely only available at shop that sells automotive paint.
You have no doubt seen vehicles driving around where someone has started to repair body,,shot some primer on and now over time rust is appearing on top of primer...This is because rattle can primer breathes, its not a sealer. Oxidization process has begun below primer. I use epoxy for most part because my projects may be a year or so away from getting the top coat. Plus it is cheap if you are painting frequently. I am using Eastwood Epoxy @ $129 per gallon paint which includes the gallon of hardener..So 2 gallons of sprayable product. AND I'M CHEAP.. Currently sand blasting and have run the same bag through the pot blaster 6 times and media is holding up well!
sorry about the long winded post
Edited by Jazz, September 16, 2015 - 11:51 AM.