You all got it right, the price sort function was broken since the beginning of MG times.
The problem is, that modules can have USD and EUR prices, just USD, just EUR or neither. These prices are stored in different table columns. On the website it was trivial to calculate the missing currency from the currency that was there but I did not get the sorting right on SQL level, e.g. calculate all the missing prices within the sort option.
I have now found a way that should improve the situation with one caveat: modules without a price do not show up when sorting by price. If I would include them, all modules without a price (price == null) would be at the beginning of the search result which might be confusing? Do you think that makes sense or should they be appended to the end of the search result?

All I want is to filter for functions (or maybe other things) and then get a list with modules starting at the lowest price.

I hope that is working better now!

Beep, Bopp, Bleep: info@modulargrid.net