This Sportsman 2000W Portable Gas Generator, which lists for $249, drops to $149 at Walmart.com. Shipping is free. This is the best price online by $40. It runs on regular gasoline, and it has two 120V outlets and one 12V DC outlet for recharging. It can run for 18 hours on a full tank. More than 30 reviews give it 4.3 out of 5 stars. Sales tax is charged in most states.