If you are using spray cans, the large 400g  car touchup cans from Sprints are good.
They are acrylic lacquer.
There are a few brands, I think the Motospray ones are usually a bit cheaper, about $9 a 400g can, although they only come in basic colours.
For undercoating you could use Solver Maxi-PSU and a 100mm foam roller sanding smooth between coats, this fills imperfections quite well.