TomTop offers the Portable High Pressure Car Wash Pump for $24.86. Coupon code "WD5656" cuts that price to $18.49. With free shipping, that's $11 off and the lowest price we could find. It features a 2-meter hose and plugs in to your car cigarette lighter. Deal ends August 31.

Note: this item ships from China and may take 4-6 weeks to arrive.