Randomized shop are an old favorite of mine for RPGs. Constantly getting in new items with an ever changing selection. There is a game called Dungeon Defenders, which has a randomized shop. However, this shop has one notably unique feature. You're giving the ability to "lock" items, so that they slot they occupy does not cycle out with the new stock. This enables players to collect enough money to purchase the item without the risk of it cycling out before they can raise the necessary funds. I find myself lucky to have Bern's Untouchable Mail in my Rarity shop, however not the funds to purchase such an expensive item. Thus, my current conundrum and suggestion. I suggest a feature that would enable players to lock shop items, so the selected item(s) don't cycle out while locked.
Given the way the game is setup, isn't that sort of what we have to do? Don't we get our pizza back when the game goes live? This card could be bonkers, and I'd love to see what it would do in a dwarf build against encumber effects. Randomly pulling one (or more for an all dwarf team) is highly unlikely or you're going to have to spend even more pizza opening chests. Earning 2500 gold is very hard to do given the current sell rates on items, especially doing so every week or two when the rare shop resets. Buying it with pizza (works out to 190 gold per dollar at the best rate) equates to roughly $13, which seems to equate to a good rare card in Magic. It seems to me that was their intention with the price points and the rare shop. The good news, you can find cards for free and a "deck" consists of fewer items than a 60 card magic deck, so it shouldn't be as expensive. But in order to get specific cards, especially legendary cards, what else can you do?
I think we make a serious error when trying to compare games such as magic the gathering to card hunter. There are several discussions that have taken place over the rarity shop. Sufficeth to say the rarity shop is intended to provide you an opportunity to spend your gold on a specific item that you want.