I want to buy minecraft for my xbox but I don't have an hd tv. Do I need one to play?

I don't think you do

Yeah, you can still play it. My TV isn't HD but I can still play Minecraft on xbox.

No you do not need a HDTV to play Minecraft for XBOX. You also don't need a HDTV to play Minecraft online either.

But if you want to play splitscreen then yes your going to need a HDTV as well as a HDMI cable.