Exit through the gift shop

I am working on the launch of the appeal to raise the funds for the music at the moment and i’m thinking of other bits and pieces we could produce to help raise money. T-shirts are a must, but also maybe mouse mats, mugs, badges, posters? How far do you go??? I dont want to have a whole shop full of tat that looks like those rooms you are made to exit through after a ride at Alton Towers.