Once you are inside your house, double click on the door, then select house vault (bottom right I believe).
Its two slots. Put two boxes or bags in there and fill them up with items.
Then when you click on your market bulletin board, you will have a tab for vault merchandise and can set prices. Anything in the vault will remain for sale for 24 hours.
As far as population, even I have to admit that people are quitting in droves. My guild went from about 20 friends, to about 5. Everyone of the people knows someone else in the guild in real life, but when one quit, and then 2 more, a whole bunch quit over the last week or so.
Yes, the population is getting higher in level, but I've never seen 2 zeks or 2 ELs, so I'm not really buying that theory. There's still rarely a 2nd TS, but that used to be very common and is now rare.
So if its just an "aging" population, you'd expect there to be two of the higher instances, and that's just not so.
I really like this game, and can't figure out what people's issue is. I love the quests and such, but my friends that have quit hated them. Oh well.