Since people aren’t buying a lot of GM’s gas guzzlers, GM’s marketing team has hit on a novel way to entice customers in California and Florida to buy certain vehicles by July 5th.

One caveat is that customers must also agree to enroll in the OnStar vehicle diagnostic service, which is free for the first year but after that will cost $16.95 a month. Each month for one year, GM will give drivers a credit on a prepaid card based on their estimated fuel usage. Fuel usage will be calculated by the miles they drive, as recorded by OnStar, and the vehicle’s fuel economy rating.

In California, eligible vehicles are the Chevrolet Tahoe and Suburban sport utility vehicles and Impala and Monte Carlo sedans; the GMC Yukon and Yukon XL SUVs; the Hummer H2 and H3 SUVs; the Cadillac SRX SUV; and the Pontiac Grand Prix and Buick LaCrosse sedans. In Florida, eligible vehicles are the Impala, Monte Carlo, Grand Prix and LaCrosse.

It works out to a saving of about $100/month if you drive 1000 miles/month. So its basically a $1200 incentive. BIG DEAL!