I bought a viagrow replacement pump with sprayers on amazon. Maybe $20. Drilled some holes and put in some foam collars and set it on a timer. Another $20 total. Performs well but I didn’t have success on my first set of clones. Didn’t ph the water and just had it sitting in the garage on a 15 on/30 off cycle. Dumped some rooting hormone and a dash of myco, but that’s all. The foliage and stem looked healthy, but the tip of the stems just got brown. I’ll probably try again soon, but I’ve already had success using sandy soil from my backyard and sink water from a dollar tree sprayer under an led bulb 20/4. I’d like to try a humidity dome, but I’m going to give the bucket another go.
Build one yourself if you're much of a DIY type of person. Pre-built units are pretty costly. Some more affordable than others though. You can also build exactly what you need -- plant counts, container size, etc.