I've always made my own.
And ended up with a ginormous amount because I couldn't get the ratio right.
So today I looked it up. And figured I'd blog about it so I could remember it next time.
Use homemade. It's cheaper, period.
Cinnamon Sugar (1 old spice container-full, 2 min)
1/2 c white sugar
1 1/2 TB cinnamon
** 5/22 Update: We prefer our cinnamon sugar to be a bit more "cinnamon-y", so I use closer to 2 TB of cinnamon.