I feel like I used to know this.. but I can't remember anymore. I think Mystery Box was up to Rarity 80? Or was it 60, like most of the Vending machines? I can't remember ever getting a Super Rare item out of it.

Or a retired item, regardless of what the fine print says.

I'm pretty sure there is no limit. Though its super rare to get a super rare :D. You can even sometimes get retireds that used to stock in the shop.

Just following up on this - Been vending every few days to verify this. I have yet to get an item above 70 rarity on any given day.

For example - today with the Bean Bag shop in which there is 1,234 possible items available, of which 387 (roughly 1/3rd of all beanbags) are rarity 71 or above. After close to 5 hours vending, I have yet to get a single item in that 71+ range. I really do think it's capped.

EDIT - I STAND CORRECTED. Less than 15 minutes later, I got a rarity 98 bean bag from the box.

yeah, they don't come up very often. The only time I bother with the box is when there's something specific I'm looking for, then I refresh, refresh, refresh, looking for that number, or a couple of numbers if I have a small list. I really hate it when a common/mundane item has the same base price of a rare or super rare.