Walmart offers the Koolatron 12-volt Air Compressor, model no. 402326, for $17.88. Opt for in-store pickup to dodge the $4.97 shipping fee. That's the lowest price we could find by $4. It plugs into all 12-volt power outlets and includes a 20" pressure hose with lock, 9-foot power cord, and a built-in 250 psi pressure gauge.