Chocolate bar's lower the cost of things on /etshop, you need to either be in PvP (warzone) to eat one or at koth. Since in that area you can consume candy.
Once you consume the candy bar do /etshop for 30 seconds with discount will be applied for, it wont show the lowered prices but it should take less etokens. Do not use /enchant, as that does not receive the discount.
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