I've been having so much fun making my own social media graphics! One free site I really like using is Quozio.
You add whatever text you want, and the site shows you what it will look like on different colored backgrounds with different fonts. What a convenient, fun tool for social media graphics!
There is a limited choice of backgrounds and you have to go with their font options, but they have so many cool possibilities.
Once you chose the background you want, you simply save it and drag it to your desktop to use anywhere you like. Simple, fast and so pretty!
You can use the graphics for your Facebook wall, Pinterest, blog posts, or even use them as Twitpics on Twitter.