This was a Gaia Lab feature, the developer is not longer here and during his time at Gaia the starting option was just four slots. It was later increased to twenty slots at the request of a gold sink. I think the next set of slots beyond this should actually require a one time minimal cash fee. In my opinion.
The most reasonable would be 25 or 50 GC a slot. This way the feature gets funded and Gaia can profit back from actually saving all of these outfits on their servers.
I use to be on an avatar site called "Whuddle World" and they too had a closet feature (well-before Gaia actually), and while you got the first (I believe) five free of charge, any additional were about 0.05 cash. I say it was worth it just due to the effort of the feature alone.
So given how much gold everyone has now, it is rather pitiful (or almost insulting) requesting more slots for gold only. You only pay once.
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