when varients (such as a 1:30 varient, not a 1:1 alternative cover) come out, retailers up the price immediately.
The theory goes like this: A comics company offers a deal that says that any retailer who orders X number of copies of a book gets a special varient of that comics. Let's just say that X=30. Now a comics store that normally orders 25 copies of a book, if they feel like it, can up their orders to 30 to get the varient. This helps the comics company out because now they've sold 5 more copies of that issue (multiplied by the thousand or so comic retailers in country). The comics store, while it may now be stuck with 5 extra copies of a book that may not sell, now has an extra copy of the book they can sell for $20-30, which more than recoups their cost on the extra 5 issues or so
(I heard someone complaining about this subject on another board who was angered that a comics retailer who normally orders 2 copies of a particular book would have to up it to 30 to get the varient, but no comics store is that stupid, and if they are, they shouldn't be in business anyway. If your store only manages to sell two copies of a book, and you up your order to 30 just for a $20 varient that's not gonna sell cause only two people buy the book regularly anyway, you deserve to lose the money)
Now, in theory, just taking the matter on those simple terms, there's nothing wrong with it, everybody makes out. Where it gets tricky is in the broader scope of things. It's an easy leap in logic to point out that if a customer is spending $30 on one issue that just came out, that's $30 he's NOT spending on other, less popular titles. It's a bit tricky, and a divisive issue.