Paint

Alright I have a few question for all you paint experets. Haha well im starting my fist full project which is a 75 dodge custom stepside 2wd (handed down from my dad who purchased it new), and I sanded it down, but dont want to attempt any major body work (welding the floor or any other rust peices, or any bondo) myself. But I was thinking if i could primer it for now till i i find someone to do this? At least some of the truck will have some protection right? Well if I should do this how do i do this? How do i prep it and what primer should i use? can i do it by spray can or will that not work?