Just got to thinking about since I started fishing back in mid 90's about the number of sonars I have purchased.
It gets scary when you think of all the numbers and models.
I don't think I would be far off guessing close to 40 different units.
Started with Lowrance for about 10 years then swung over to Humminbird.
Couldn't guess how many $$$'s that would cost, other than MANY!