Hello :) Does anybody know for how long the quest shop items will stay in the shop? I'm asking because I still need some for my gallery, but don't want to buy points.

no user knows the answer to this. The reason the QS exists is to give value to items over and above any particular game use, to give sP to those who don't wish to play games/restock/vend and to engage in a little inflation on Subeta's toy economy. So far, the official response for people getting everything that's in there that they want, is to add more items. I haven't heard or seen any time limits on them like items in the Millionaire Center or the Subeautique do.

I do almost all the quest that grant QP, and I get around 20 per day. Do the things you want cost that much?

thank you for your answer. I thought they retire some day like some Vesnali and Masquerade items. Yes I still need the 20point Saggi items and some of the higher priced beards from Carl, but also have to buy items when they are new released :D