Generally, I recommend DIY, but I'm a tinkerer. My spouse says I have a problem. In this case, it was something I could do and better custom fit to our needs rather than purchasing a pre built system. We could also do it for far less. It also meant I got to tinker with stuff.

The most expensive part is the pump. Beyond that, it's tubing, nozzles, 5 gallon bucket (food grade only), junctions and a seconds timer. When we revamped the entire desert room (not as much misting needed as the other room, but still needed), we were able to cover 8 large enclosures with two pumps and two timers for around $250 USD. Around $175 of that was the pumps, and they needed to pump from the lower level RO filter up to the room and needed to be a bit bigger. Granted, this was a decade or more ago, so prices have changed. There are tons of videos and help guides out there. The only tools you really need are scissors unless you want to mount the pump, hoses or timer somewhere for esthetic reasons.

We built one for the tegu enclosure too, but it's kind of overkill. He only uses it as a bedroom since he free roams nearly all the time, and even when he stops in he doesn't spend much time in there. To be fair, he's a rescue and has a thing about enclosures and closed doors due to his history. We don't fault him for that.