Look, I dont want to put you off, but Dark BASIC is nothing like Game Maker.
For one thing, you dont have a workspace and stuff. It is all coding. All of it. Apart from making the 3d models of course.
If coding isnt your thing, and you would prefer something more 3d click 'n' drag-ish then you should check out the 3d game maker.
If you think you want more power over your game, get FPSCreator. If you still want more power then Dark BASIC is the way to go.
I think you should buy classic first, or even better, just get the trial. Then, if you think that Dark BASIC is for you, get the full thing.