you can get tracker controllers for about $100-200 depending on required features.
Having purchased commercial controllers for more and less than that, I've been totally unimpressed.
I've built my own, and been sent others to try.
They've worked.
In the end, I've gone back to time-based tracking.
It's ultimately more accurate more of the time.
Clear, cloudless days are a doddle to track. But most of the tracker controllers come unstuck under overcast conditions, or partially overcast, or overcast mornings, etc.
Probably my "ideal" controller will be time-of-day with "fine tune" sun-seeker.
I haven't built it yet
PS: I've been working on an entirely and hitherto unseen technique, which I feel will work particularly well. It's only been made practical by recent innovation in other not-immediately connected technologies. Once I get time and interest back and build one, I'll post the results - but I expect them to be "brilliant".