This is a plugin for BetterBags. It creates filtered groups for price ranges, and automatically adds items to them based on the min buyout price, this uses Trade Skill Master.
Right now it should work for all items that have an auction value, other than battlepets (this is something to do with cacheing of items, BetterBags sees all caged battlepets as the same item).
I might fix this and possibly add options/increased functionality, I also might not, if someone else wants to do it, go ahead.