Sam's Club offers its members the Sportsman 800-watt Portable Gas Inverter Generator, model no. GEN1000I, for $158.64 with free shipping. (Non-members incur an additional $15.86 surcharge.) That's the lowest total price we could find by $80. It features 800 running watts (1,000 peak watts), a 0.55-gallon tank, two 120-volt AC outlets, one 12-volt DC outlet, and automatic low-oil shutdown.
Update: Specs corrected.