Okay, so I've read at least 10 sites telling me how to do this. I click get info on the .icns file that i want, get info on the folder/file i want to put that icon on, copy and paste it onto the thing in the corner, and i get this. It just has the generic ICNS picture. PLEASE help.
No need to buy CandyBar. There must be something wrong with the files (I'm not really sure how .icns files work, but it's a frequent problem). Use img2icns to convert them to a usable .icns format for free.