This website is a bit of a hub for other tutorials, giving links to other resources and compiling them all in one helpful place. It's good to have a place to see everything else there.
This is a useful resource for beginners in Game Maker, showing all the different things the program is capable of. It's also good for people who aren't sure whether they want to buy it or not, because it describes the program very well and gives a review of it before the tutorial starts.