I think (and I think most of us can agree on this) that the guild store is pretty bad set up. Here are some reasons why and suggestions to what could be done:

+ A way to type in what you want and search. Having to look through literally 30+ pages to find the item you want can be really annoying (ecpesially when you find out it wasn't even there). A way to simply search up the item would solve this.
+ The materials section should have a couple of smaller sections that would go for different things. Here are just some examples:
Matierials >
Resources (iron ore, high iron ore, jute, rough maple, rawhide, etc).
Alchemist resources (things used in alchemy like different types of flowers, etc).
Runes (oko, makkoma, deteri, etc).
Recipes
After writing that I realized that you might as well change the name from matierials to crafting.
+Change the name of "other" to michellanous and add some sections:
Michellanous >
Crafting items (racial ingredients, stuff that improves items like honing stones or hemming, etc).
Fish
Traits
Lure
Tool
- And "food" should be taken away from that section because there is already a food section.

Also I don't get the matierials section. Matierials pretty much means all items because you can find anything there from armor, potions, resources, food, ingredients, etc, well pretty much anything. And that makes no sence at all and needs to be done something about.
If there's anything else that you would like to suggest or something you disagree with just comment below and let's get a discussion moving so hopefully zenimax can see this.