Jagex sometimes does a "going away sale" in January or February, though this has not been announced yet.Items will go on sale for a huge discount, then be removed from the store when the sale ends.
Mefistofelezsaid: By the way, the "Earn Runecoin" option is hard work. A lot of those links won't pay out What can I do about that?
PeanutsLabs Surveys tend to be the most reliable sources of RC. You'll have trouble matching for surveys though. You can also filter offers to "lowest rewards." A lot of the ones that reward fewer RC only want you to visit their site, or click through a 10-page slideshow, or sign up with a throwaway email for something. I highly recommend an adblocker when doing this too