http://serebii.net/itemdex/rarecandy.shtml
If you look at all the locations Rare Candies aren't very rare. In fact, they sell them at shops. If you apply logic to it (something Game Freak doesn't have, but still apply logic to it) then if a shop gets Rare Candies, people are actually delivering them to the shop. Meaning there must be quite a lot of Rare Candies in the Pokemon world. xD
There are more Rare Candies than PokeBalls found on the ground. Seriously, there not as rare as they used to be. xD
Hope I helped. :)
Source: Above Link
