I own a bunch of AP cages T8's T12's, and soon T25's Top notch quality and great customer service. If you have any questions I can probably answer them.
DIY is a little more complex than just building, you need to source the proper materials first. Wood doesn't handle humidity well, and is very hard to heat through. It can be done but by the end of the build you probably aren't going to save that much money.
PVC sheets, and melamine are best.