Ok well i found a glitch that has to do with buying a Hyrule Dagger/Scimitar/Red Mace.
I did some experimenting on this and came to a conclusion:
*when i bought a Scimitar, my Event Coins never got taken. Before the purchase i had 30 EC, after the purchase i still remained with 30 EC
it is not just the scimitar that provides this glitch. Another user told me his EC never got deducted when he purchased a Hyrule Dagger.