Motorstorm: RC - A new kind of free to play?

In the last few days I have been playing a lot of Motorstorm: RC on the Vita. And I think it is an amazing game! I would have definitely paid 10 dollars for it, but not only is it not 10 bucks, it is free!

Completely free, courtesy of Scion or course (which actually has no marketing effect on me, since there are no Scion cars in my country)!

Now, free to play games always strike me as an unattractive proposition. Since there is no free lunch, free games usually bait you with just enough to make you consider spending money.

Sometimes they do that by locking out items, sometimes they make them so expensive in fake money, and so hard to progress without them, that you pretty much have to buy some fake money.

But what they have in common is that it is difficult to have a full (or very fun) experience if you keep your wallet in your pocket. And I'd always rather pay whatever the cost is upfront, and then just have the full game available.

Seeing the DLC pouring in for M:RC, I immediately though "ta-da, there you go, it's a typical free to play game that charges you for everything". Except that the more I play, the less I think that this is true. For one, there is far more stuff to do in the actual game than what is available in the payable options. And although there is a ton of cars available for DLC purchase, I have never found a challenge so far that required me to buy a new car, or else I would never be able to pass it.

What I am experiencing is actually a great free game. And how do they make money? Ads! A giant ad for the new Scion every time I play the game. They also have the DLC, but I imagine that the bulk of the cash comes from Scion.

So, in the end, my question to you all is: Is this a viable option for a new kind of ad based free to play games? A free game that offers you the option to buy DLC, but still make it worthwhile even if you don't spend a dime? Would you be willing to stand ads in order to get a free game? Is this even possible for other games, or is this just a one-time thing?

I for one would be more than happy to see more games draw revenue in non game-breaking ads, if this resulted in more free or discounted games.

What do you think? Are they into something or am I completely off base here?