Look, I've already told you that there are just too many variables. What one person acheives will be different from another. As frastini also tried to point out, those variables can include the specific MB you are using, the location of the thermisters it uses, the program that is montioring the temps, the case it's installed in, the locations of the case fans, the airflow of that case, the kind of thermal paste you use, how much paste you use, how well you get the HSF installed on the chip, how good your fan on the HS is, and so on. Each of those items can make a difference in what you vs someone else will get. So no one can say you will get "at least XX degrees C" with that HSF. If they did, they would be lying; or at the very least, misleading you.
Maybe $6.00 (plus shipping) is too high for you; I don't know. If that is the case then start by trying to change as many variables as you can with what you have; location of the fans in the case, airflow of the case, installation of the HSF, the thermal paste, etc. All those can be altered by you with absolute minimum costs. It may net you a degree or two. If you want more then you will have to spend some money.
Edit: You can find a review of the GC68 and Golden Gate (plus others)
here. Keep in mind though that even these temps will vary from what you get. This is just a guideline of sorts.