Walmart offers the Porter Cable 4-Gallon Stack Tank Electric Air Compressor, model no. PCFP02040, for $99 with free shipping. That's the lowest total price we could find by $100. It features a 1.1-horsepower induction motor with a cold start valve, oil-lubricated pump delivering 3.4 SCFM at 90 PSI, and 135 PSI max working pressure.