When I started my tool collection, almost everything I got was from Harbor Freight. I got one of each type of air tool they had. Some I've never used, some I use all the time.
I was able to spend about $150 on all these air tools. That's about the price of one top-shelf air tool. I am by no means saying the quality is the same, but its a great way to get the basics, then as time goes by you can see which tools you use the most and invest in the higher-end versions of those.
I now have an extremely nice cut-off wheel tool, but I also have my Harbor Freight original as a backup!