If you are going to be doing alot of model builds, I would recommend investing in an airbrush. It will save you money on paint in the long run. And, you don't have to get super expensive airbrushes to do a good job. The Iwata Neo or Badger Patriot are fine starting airbrushes. The compressor will cost a bit, but you don't have to get an ultra expensive compressor either.
If you do go with airbrush, I can recommend model paints because I've used almost every paint out there, including newer market ones.
Recommended Paints:
(lacquers or alcohol based paints)
1. Mr. Paint (MRP) - THE BEST model paint out out there.
2. Mr. Color - Not to be confused with Mr. Paint. Not made by the same company. These are produced in Japan. They are fantastic but thicker than MRP for more coverage.
3.Tamiya Acrylic Bottles - Almost as good as Mr. Color, but some of their range can be a bit chalky, particularly the whites. Most non-white colors are awesome, though.
(Water-based paints)
1. Mr. Paint Aqua (MRP Aqua) - This line of paints is fairly new, and they don't have all their colors built up yet, but MRP aqua is everything Vallejo Air claims to be, but actually works much better. You won't get tip dry as easily with this stuff and it goes on thin and smooth. You have to slowly build up layers.
2. Vallejo Model Air - This stuff is great, but it's advertised as being able to use in the airbrush right out of the bottle. While that is technically true, it doesn't perform very well straight out of the bottle. The best way to use Vallejo Model Air is to thin it 1 part Vallejo Airbrush thinner to 3 parts paint. Also, for every 10 drops of paint, I add 2 drops of Vallejo Flow Improver to that same mix.
3. Mission Models Paints - These paints are a little different in that they have to be thinned with a special thinner. They can only be thinned with Mission Models own thinner. Some people prefer these over Vallejo Model Air, but they have a more limited color range. I personally couldn't get them to perform as well as Vallejo Model Air, but perhaps it's because I need more practice. Other people swear by them.