I always carry a wedge with me. I sit on it or put it under my heels when I squat. It is extremely helpful when your heels refuse to touch the ground.
Although these aren't the blocks I have, I prefer the cork yoga blocks. They are more sturdy than traditional blocks. Blocks help raise the floor a bit if you're not extremely flexible in certain positions.
Anyway, these are just a few of my favorite things, which I use to help my inflexible ass during yoga! Namaste...bitches!