Its been more than a few years since I have done any painting and the rear bumper on my truck is blistering at the far right side, not a big area, just about 2 inches around. I have painted panels and even a couple of complete cars several years ago. The color is Brillant blue with paint code of 903562. Would anyone know how much paint it would take to paint the entire bumper and I'm assuming it would be a base coat/clear coat? Also, would a epoxy primer be suitable for this and should I remove all of the old paint or apply the primer over the sanded original paint? Also, since there are no paint stores near me, is there anywhere online to purchase the paint products? Thanks so much.

You should be fine removing the damage and if the rest is in good condition and not delaminating, it will be a suitable substrate once prepped. You don't need to epoxy prime the entire piece, just the bare metal areas. A pint of base will more than cover that. Smallest amount of clear is usually a quart.

For the base: https://www.carpaintonline.com/products.php?PPGCode=903562&PNId=26&SPCId=44

Clear:
http://www.smartshoppersinc.com/kirker/clears.html

There are a ton of other places I'm sure. Those are the ones I readily know of.

On the blistered area, after you sand/clean, I'd suggest a rust converter first to stop rust in any pits, sand then epoxy prime. If needed a little spot filler can go over the epoxy, then sand and re-prime. To get it smooth, a coat or two of primer/surfacer over the whole bumper will help then sand with fine paper. For small projects, I have had good results with Rustoleum auto primer in spray bomb.

One suggestion... before starting it wouldn't hurt to check WW Sherman or one of the other body parts vendors to see what a repop new one would cost... then decide whether to repair or replace. I spent many hours repairing a front bumper cover for a Neon (1 hole, 2 small tears) then found out a new one was only around $70. Still it came out fine.