Where can you buy game designing software to make your own video games

There are a few places. You can check http://www.yoyogame.com or http://www.thegamecreators.com for some. Yoyogames has a free game creator called Game Maker, which is free and can make 2d and basic 3d games. On The Game Creators website, you can find some cool game makers for 2d and advanced 3d games, and most are easy to use, and it has good level makers and model makers.