Why can’t I purchase stock in the alliance shop?

The alliance shop has 2 sections (tabs at the top).

The 'Shop' section is for any member to buy from as long as there is stock of what you want.

The 'Stock' section is for R4/5 members to select which stock to put into the shop for others to buy. If you are in the Stock section and not an R4 / 5 then you will not have permission.

Ask in the chat for one of the leaders to add the stock for you.