BagSaver will help you keep your bags as clean as possible.
I wrote this addon after having enough of my bags being full as I'm levelling/doing dailies/instancing. The goal of the addon will be to keep your bag slots clear of things you don't want, and assist you when your bag does somehow become full in finding the optimal (read: least valuable) item(s) to discard to make room for something better.

All suggestions and feature requests are welcome!

Current features are:
Automated selling of gray items whenever a vendor window is opened
Automated selling of soulbound items that could not ever be equipped (i.e. quest reward staff taken by a Rogue to sell)
Automated selling of soulbound armor that is below your primary armor type (cloth, leather, mail, plate)
Finding the least valuable stack in your inventory for youwhen your bags are full and need a slot for new loot.

Slash commands (/bagsaver or /bs):
/bs config:    Open addon config menu (also found in Addon tab in Blizzard's Interface menu)
/bs reset:    Resets your config to defaults