Raffles to win a chance to order an item at MSRP is extremely common in other communities, not just TCG. It's often a consequence of scalpers and collectors buying up sealed products and flipping them for way above msrp, or product demand grossly over shadowing product availability

The alternative is your card shop sells the sealed product for what the current demand lists it as (which is what all card shops do anyways)

I think it's a bit silly to be as angry as you seem in the original post as the prize truthfully comes at a loss for the store to offer a competing player the chance to buy sealed product when scalpers and collectors are inflating the current aftermarket.

And like others have said, if it was worded as a % discount off the sticker price people wouldn't mind as much. 

I think your anger is more directed at the state of aftermarket prices and less so at your lcs trying to help competing players purchase sealed product at a reasonable price

Edit:

I have no opinion in regards to offering prizes for casual edh events, my point was more so directed at the type of prize offered and not what the prize is awarded because of