CPO Outlets via eBay offers the refurbished Bostitch 6-Gallon Oil-Free Air Compressor, model no. BTFP02011-R, for $99.99 with free shipping. That's the lowest total price we could find by $15. It delivers up to 2.6 SCFM at 90 PSI and includes an air hose.

A 1-year warranty applies, but it's unclear who backs it.