If your are building small models, I would used Tamiya, Testors, Vallejo, etc.
Larger models (1/24) you can get away with large rattle spray can, but the colours are limited. Some brands have adverse effects on some models, so test out on sprue first.
TazMan2000
The smallest model I'm working on is a Polar Lights 1:1000 Romulan Bird of Prey. The largest is probably going to be a Pegasus UFO.
I lack an airbrush and I'm already pushing $250 on a couple of models for materials. I was hoping I can get by on the rattle cans... :/I would try to order Tamiya paints online. If that’s not an option, and all you have available is hardware store spray bombs, I would decant them and spray through an airbrush.
These models really don't have small parts...they are very simplistic.If you use an airbrush, you can get a thin coating that will not cover up any detail. Of course, for a 1/1000 model, if you're painting panels of different colours you could use a brush, but the base coat should be airbrushed. Tamiya paints, even in their spray can format, can produce nice finishes, but its easy to overdo.
I do small work as well as large pieces, so I have all types of spray paint and bottled stuff.
TazMan2000
...maybe I will just try brush painting...spray painting seemed to be the easier way and I can't see the investment in an airbrush at this time.... :'(