Some ideas are weird, some just QoL. Maybe none of those are interesting for you, but could inspire you.
- Being able to place limited, timed offers in advance, as many as i like. So that i can theoreticly plan christmas for the next 3 years (maybe same as your "special offers")
- Being able to place discounts by price. Every item that is higher then 15€, gets a discount of 10%. So you don't have to think alot about the perfect discounts. This would be universaly for all items in the shop or per page.
- A sort function, so i can sort for "most bought", "lowest price", "highest price", "newest", "oldest", "least time left" (for limited offers). This would ignore the selected categorie and show instead a page with all items combined. Or you make it per page.
- A shopping cart, so people can put in a lot of things and get a discount at checkout (toggleable)
- A gift option, so i can transfer a bought item to the itemshop inventory of another player, with a timed option (as example: if someone has birthday tomorrow, the item gets delivered that day)
- A option, where you can preview the items on your own character, only locally for you visible. Especially great for effects like shinings.
- A option for the player, where he gets a in-game message if a item he whitelisted has a discount (email would be great too, but should be toggleable and deactivated by default)
- Lottery, where people can buy a ticket for 0,50€ (configurable) every day (configurable) and have a chance to win a high priced item from the shop or coins. The lottery number (as example: 241 (max 500, configurable)) must be put in by the player manually. If nobody hit the right number, the price stacks on the lottery next day.