Good luck in purchasing your 500 CLD; however, because you are new here I feel that I should point out that not everybody in EU has a stack of 100 CLD just laying around. Normally most avatars have a handfull of these things or at most 20-30ish. Not many people can afford to have 100 CLD just laying around collecting dust (roughly 40peds week in revenue but around 100k to 150k peds tied up in the CLD)
It would be easiest to purchase them in small quantities, but probably not the most effective for you since it is time consuming.
Edit: Hulk does have a stack of 100 CLD last I recall... unless he has sold that stack already.
~Danimal