I make and sell quite a few salt/pepper grinders. The vintage kit wound up being kind of pricey and didn't sell. Pretty much had to give that one away. I've not done the one handed. Will be interested to get comments. Seems like something that might require more hand strength than the folk at my shows have

. My best sellers are the grinder sets with ceramic grind mechanisms that I sell in sets. The "adjustable grind" feature is a strong selling point. One thing I've noticed (on the set on our dining room table) is that the ceramic mechanism isn't as durable as steel - but it also isn't corroded by salt. Trade-off. That set lasted 5-6 years of daily use. I just replaced the mechanism. Love it for sweet corn in the summer.
Price point is directly related to venue and perceived value. I do mostly juried "art" shows. I hate competing with hand crocheted toaster covers. Even so, my area (mid-Michigan) doesn't support high-end stuff. Most grinder set sales are in the $30-40 range.