Fake YSL Touche Eclat?

[cakedup]

I normally buy via Amazon or Ebay to get a better deal, but never sure I'm buying the genuine thing.

Is there any sure way of telling? Do you buy cheaper online or get it from Boots etc. to make sure you're getting the real deal?

i am allergic to it, so don't buy it at all. I often use off shore companies like beauty bay and strawberry net for cosmetics though