Avoid them. The way they work is with specially designed tines that wear out relatively fast. They are not very useful as the gear speed of the wheels prevents effective cultivating between rows. For that matter, avoid entirely the typical craftsman husqvarna other name whatever cheap tillers with stamped steel gear boxes.
I purchased a Troybilt horse tiller used for $400 10 years ago. I use it HEAVILY every year. The motor went out 5 years ago and I replaced it with a new Briggs industrial 8 HP motor. I replace the tines about every other year for roughly $140 with new case hardened tines. I’m convinced it will outlive me.
If you want to purchase a troybilt horse, suggest looking on Craigslist in your general area. I often see an electric start Horse for $500 to $600 in very good condition. Do some due diligence and you will wind up with a tiller that works circles around the cheap junk available today. Please note, troybilt pony, bronco, tuffy, econo-horse etc are not in the same category as a Horse tiller. Also, there are plenty of very old horse tillers advertised for high prices. You want a recent model horse tiller with the 2 speed gear box.
In the very hard to find category, there are some older tillers that are excellent if not completely worn out. I have a Tillsmith front tine tiller that is incredibly useful for cultivating in the garden.
Here are a few examples from Craigslist:
This is a good tiller but overpriced as it is manual start. If electric start, it would be worth $550 to $600.
This one is electric start but is the older single speed model as you can tell by the tires and tecumseh motor. It is a usable tiller, but only worth $250 to $300. https://huntsville.craigslist.org/grd/d/hazel-green-troy-bilt-horse-tiller-with/7288268271.html
This one might be a decent tiller, but is not listed correctly. Need to verify it is a Horse, not Econo-Horse and that it is the 2 speed gear box. Electric start is nice but not necessary. If it ticks all the boxes and the tines are in decent shape, it could be worth $300 to $600. https://jacksontn.craigslist.org/grd/d/mc-kenzie-troybilt-tiller/7288667363.html