Walmart continues to offer the Stanley FatMax 140-watt Power Inverter, model no. PCI140, bundled with a Freestanding Keychain LED Light for $19.98. Opt for in-store pickup to dodge the $5.97 shipping charge. That's $5 off and tied with our mention from two weeks ago as the lowest price we've seen. It plugs into your car's DC power outlet and features a 1-amp USB port, two AC outlets, 3-foot cable, and mounting kit.