Bumping this one up, as shops currently are mostly one-time wonders nowadays, and given their rarity and quick escalation in price when restocking, the old behaviour was not imbalancing.

IIRC this was always dependent on the current number of items in the shop. (plus the available floorspace, leading to weird tricks like stacking all of a shop's stock on a single tile in the hopes of it generating more stuff)

Nowadays it's only dependent on the number of items in the shop. And if the shop is pretty full, not many are generated. Why restock when you don't manage to move stuff?

If only shops did not generate stuff like clothes [-1, 0] or short swords (1d6-3), then maybe, just maybe, shopkeepers would be able to sell more stuff.
Greedy bastards can appraise unided items with great accuracy and rip you off in the process, but can't figure out their garbage will never sell?
Come on.

Well, I believe it should be reasonable to make PC not the very only customer in the entire Ancardia... I'd restock these items while PC is away. The lower the price the higher the probability to restock (considering general folk in Ancardia aren't heroes who need the best only and don't own much money. Artifacts can be just kept forever if you don't wanna be evil.

Please find attached a save file of the case (3.1.0). I had bought the ring shop empty and it restocked with a single ring, as seen in the savefile. When I waited further on the level, the next arcane mumbling was another restock of only one ring, which also had generated on top of the existing one. I'm still saying there's something funny going on here...

BTW, shop prices only increase if (a) either there is 1:6 chance and your moves are > 5000 or (b) at least 1/4th the shop size is refilled with items. So there usually won't be price increases if but one item is replenished.

Side note: If there are many monsters in a shop, the likelihood for restocks (and the restock size) decrease.

Fixed.