Inventory management sucks if you are not a subscriber. You will either need to start picking and choosing what sets to save and which to let go or stop hoarding other things such as crafting materials.

A second account works wonders to hold the crafting items or any other non bound items, which will free up inventory space for sets. Can occasionally find them on sale for decent prices, last sale was $9.90 for standard version.

I have my second account for use with the trading guilds I belong to and set up as follows

• Character 1: Gets mail from main account, decons useless crap, put items to save in bank and items to sell in guild trader.
• Character 2: Holds Alchemy mats.
• Character 3: Holds non max level Blacksmithing mats, sells stacks of 100 at guild trader.
• Character 4: Holds non max level Clothing mats, sells stacks of 100 at guild trader.
• Character 5: Holds Enchanting mats.
• Character 6: Holds Style and Trait materials. Sells in stacks of 200 at trader when needing to fill trader slots.
• Character 7: Holds Provisioning mats, sells in stacks of 100 at guild trader.
• Character 8: Holds non max level Woodworking mats, sells stacks of 100 at guild trader.

This essentially gives me not only the double space subscribers have, but also an additional 5 guilds to trade in, and someone I can mail to anytime I find myself full. I have also leveled the characters enough so they can all do the equipment writs at max level. Not that that's needed but it brings me in some extra writ vouchers or gold if I ever decide to start selling them.