Check the used market as well.
A big brake (that will comfortably bend 1/8 aluminum) will be expensive new. Otherwise you'll take a
smaller brake and push it beyond its capacity, never a good thing.
Look into getting a
hydraulic press and a bending die to make Press Brake (see
this illustration for the principle). The die can be home-made from large steel angle that's been machined.
Think about how a brake is made and then consider building one yourself (like a
bigger one of these). I mean, if you can build a robot, you can build a brake. Materials will cost $2-300.