KOBALT 30-Gallon Two Stage Portable Electric Vertical Air Compressor. I was lucky to grab this last year at $125, and I just saw that it's on clearance at $291. It's reg. $529 and sometimes on sale for just under $500. Note that this is a oil-lubricated, two stage pump and not very loud.
This looks like it's very ymmv since most of the stores near me are still at the full price. This is a great mid size compressor if you can find one.