Extension tubes

[Mr.Rocc]

Hello all,
So im getting more into my coral photography and I need some help finding and deciding on what to buy. I need an extension tube for my camera. I have a canon rebel xti and i really want to be able to take better pictures close up. Whats my best bet here? I dont have the money for a macro lens just FYI
Thanks in advance

 

[Tuffyyyyy]

Is this kind of what you're talking about?

http://buildinganobsession.com/products/top-down-camera-box

Or are you talking about a different lens or something?