So I'm not sure if this has ben mentioned, didn't see a post about it but some nice info from Square's lodestone site about retainers and upcoming changes.
"Q. I have read that there are changes planned to improve the market system, but is there any more specific information available regarding these changes and the direction the market system will take?
A. We have continued to receive copious amounts of feedback regarding changes that players would like to see made to the market system. As a result, we are planning a number of revisions and additions to the system, the first of which are scheduled to be implemented in the next one to two weeks.
Specifically, market wards will be organized according to specific item types, making it easier to consolidate similar items in the same area. Further, if an item sold within a ward corresponds to that wards’ item type, the tax incurred will be reduced. Items not of that ward’s category may still be sold, but the tax imposed will remain the same as it has up until now."
Then the page goes on to list the new names for market wards and what items will be taxed less in those specific wards (should be sold there).
Should make searching for one single item you need alot easier than its current state.