I think thats about right.

A Jade is the cheapest one i have ($60?) but now lists for higher

Seedsigner just bare parts may be $40 or $50 but typical casing and buttons drives it up to $80+ is my experience.

If you count it, Tapsigner is as low as $30. I want to get one to try out

Anything under $100 is a good price for a hardware signing device, and under $200 for feature rich devices