You cannot make anything worth buying with the free version of game maker. You're better off learning another program then.

Game Maker was originally made as a teaching tool for programming teachers, to use in their class. It's was made for beginners, and intermediates. Recently, they have started to target professional game artists aswell, with Game Maker: Studio, hence the high price. You can probably still purchase Game Maker 8.1 for 15 USD, which will give you all the same capability as Game Maker Studio, but you will only be able to export to .EXE files. Most sites and distribution platforms won't accept .exe files, so it's not viable for commercial use, but there's still plenty of support from http://gmc.yoyogames.com/ and http://sandbox.yoyogames.com/ . If you don't have 80 USD to burn, but want to learn programming from Game Maker, Game Maker 8.1 is a definite recomendation, as a place to start.

Hi :)

You can also put this into an Execute Code action, in the room_start event, of any object in the room:
background_hspeed[0] = 1; // Horisontial speed of background 0, set to 1
background_vspeed[0] = 1; // Vertical speed of background 0, set to 1

This way, you will also be able to use decimal numbers such as 0.2, which you cannot use if you do it in the room tab. And you can also use this to change the background speed dynamically throughout your game.

I taught myself programming when I was 9, only using Game Maker. The first 2 years I used drag and drop, then I slowly moved over to GML. I have now used Game Maker for over 10 years. In my opinion, Game Maker is the superior 2D engine to make games on. If you want to make 2D games, Game Maker is definitely the way to go.