I guess I always thought that the value (or worth - these are the same, right?) of something in an efficient market is its last sale price, and because vim is widely available for free it's an efficient market with a last sale price of zero.
I would agree with, "The value / worth you derive from your use of vim is greater than 100 euro, assuming you actively use at least one of your vim installations." But then again you could say something similar about most common free or nearly free tools and consumables, for example cutlery, oxygen, and linux.