Is your feature request related to a problem? Please describe.
Yes, having to spam click is annoying.

Describe the solution you'd like
It would be great if we could shift+click for a stack of items, and control+click for 16 items, and alt+click for 32 items (in every shop UI)

Describe alternatives you've considered
None

Additional context
Having them be regular game keybinds could help some peoplel, but shift & control are good by default.

I have no plans on ever adding key binds to multiply the number of times a trade is interacted with per click, as multiplying a trade that sells 2 stacks of an item by 64 would result in a royal butt-ton of items all over the floor as the don't have enough inventory space for 128 stacks of items. If you wish to buy items a stack at a time, convince the person selling them to sell them by the stack instead of individually (or have two trades, one that sells them individually, and another that sells them by the stack).