Ok. Now that I've introduced SpeedFan, please, let me tell you a few words... Developing SpeedFan has required (and still requires) really *a lot* of work. Running this website, answering emails, hunting for datasheets, purchasing hardware... It all requires a lot of work.
SpeedFan is freeware. You can use it without paying anything.
Anyway: if you feel a donation would be a nice way to support SpeedFan and its improvement over time, it will be appreciated.

If you can't find it, feel free to do multiple payments to reach to amount you like ;-)