Driveclub is an upcoming PS4 racing game that, in the absence of a next-gen Gran Turismo, is something a lot of people are looking forward. Just be careful which version you buy.
To help lure you in, a "free" copy of the game is being made available to PlayStation Plus subscribers. It's obviously scaled down, with only a few tracks and cars available, although it will let you try out every game mode.
If you like what you play and want the full package, you have two options. There's a full copy being sold on both Blu-ray and the PSN store, which will be your standard racing game. All the tracks, all the cars, you know the deal. You'll need a PS+ subscription for multiplayer, but everything else is yours so long as the disc (or your HDD) and your PS4 survive.
Or, you can "upgrade" the free version to the PlayStation Plus edition, retaining all progress you've made. This is slightly cheaper. Like the disc edition, this will give you access to everything, only with a catch: it will be tied to your PS+ account. Stop subscribing and you won't be able to access the content, even though you paid for it.
So, um, yeah. Screw that. Get the full version or don't get it at all. Below is a trailer that tries to explain all this, and I promise you, it is not satire.