Pay for your inventory.

[LunaHoshino]

Then you don't have as much as you think? I have one retainer entirely filled with weapons and gear for potential glamours, and one entirely filled with mats. It's not exactly difficult.

But why do you need an entire retainer for mats? The only mats I keep around are the rare/expensive ones that aren't easily obtained. Otherwise, I just buy what I need off the MB, craft whatever it is I wanted to craft, and then resell the rest. I don't keep mats precisely because they're a huge waste of inventory space when I can just go buy what I need when I need it.