sheet metal/paint technique question

I'm planning to begin some (I think) simple sheet metal and rust repair on my 69 Dart. I've never done it before, but an feverishly reading and soaking up all the information and technical know-how that I can before I begin.

In the end, I'll plan to have the car professionally gone over and painted. But, I hoping I can cut down on the end cost by doing some of the grunt work on my own. Which leads me to this post.

If I repair a section, for instance either patch in sheet metal or simply just work out a dent and apply body filler, is there any long term negative impact to me using some sort of a spray can primer over the repaired area?

I know enough that bare metal shouldn't be left exposed. However, I won't be able to get the entire car squared away and repainted in a short period. I'll have to repair small projects here and there over time. So, I'm wondering if I can work on a small area and protect it with a spray can primer. I don't have an air compressor to shoot primer.

And finally, do you guys recommend a particular brand of body filler and primer?

Again, thanks. You guys are always great for this stuff.
Stepper