Hey.
Chapter 7 is going to have an Auction Hall. In Auction Hall you can bid and won items, most likely they will cost more gold than buying from stores. But in Auction Hall, you can buff items and spells you forgot to obtain from earlier chapters. For example, if you missed "Toxic Sting" from chapter 2, you can buy it from here.
So, start to throw items here, what the Auction Hall will offer.
The Auction Hall will be somewhat similar to this video from Final Fantasy 9.
[youtube]http://www.youtube.com/watch?v=616H1rr48iA[/youtube]
Items that will be offered at Auction Hall.