For a long time my compressor was a 2 hp 110 v. Sears. it worked OK but had a lot of down time waiting for the tank to fill.
The extra tank is a great way to cheat. Just plumb the outlet of our existing unit into the other tank and put an outlet in that line.
There are new ones, but a good source is someone with a dead compressor head giving away the tank,
Keep you eye on craiglist or local ads.