I've made my own several different ways and bought a couple different brands.
Making the popular aluminum framed enclosures is not too difficult- just time consuming. But you can get everything you need at lowes or home depot. I made 20 last summer- each one took several hours, but I'm not sure I was using the right spline- spline took a bit of force to get rolled into the grooves. There was only one size spline sold in bulk, and I assumed it was correct for the the framing sold, but in retrospect, it probably would have been much easier if I had skipped the bulk spline and experimented with some of the smaller diameter stuff.
Here is a good video on doing your own:
http://www.youtube.com/watch?v=AnNl5IMXFCI
In the past I've built a few kinds of cages- wood framed with screen stapled to the frame, pvc framed, with screen held in place by split lengths of pvc screwed to the pvc framing. My favorite for viewing were screen cages with plexiglass doors that I simply oriented to the north side when they were outdoors- lizards got sunlight from the screen and I got a great view through the doors.
But wood, even painted, rotted pretty fast with the misters going and all. Those lasted only a few years. The pvc was kind of a pain to work with and it was impossible to get bug proof door frames.
So I used reptariums for a while- they had pros and cons. Pro- the 175s I used were larger - 29"x29"x 48 which was pretty roomy for most chameleons. They were also really cheap. On many I built my own strong pvc frames out of 1" pvc and then purchased reptarium replacement covers and saved $30 or so per cage. But crickets and superworms could chew holes in them, sunlight eventually breaks them down, other lizards like bearded dragons scratch through them, so I was always continually patching them. Then in the end, I learned the hard way that they are flammable. So I'm not a fan anymore.
After building a bunch of aluminum window frame cages last summer, I bought a bunch from
http://diycages.com/
I posted a bit of a review just now and deleted it- that's not really what you are looking for and I don't want to say anything negative about the cages without discussing with the manufacturer first if I ever re-order. I really liked him as a person when dealing with him. Overall, I like these cages, but they aren't without their irritants.
Most of the manufactured cages have a similar design.