All in one backpack? Why not just use the *open all bags/boxes* command? I think the default toggle is , - anyway check the Interface options its in there somewhere =)
If its for the bank - your best bet is to find a bank mod that has an open all toggle. I use DeaconBank - it is very compact and has toggles to open all vault storage and all backpacks. Very sexy mod.
Hmmm as to pricing items on the run (btw sell in town rather than to outland merchants for better prices). Thats just a knowledge that will come with time. You get the best money for: Fabled body drops (like a wasp sting), looted curiosity treasures are special and pay well. Collection items and study items for a race (like gnoll, orc etc) only pay 7-8 copper at the merchant BUT some of these can be quite rare and you can get good money selling through your vault. To quickly find current market prices for items I suggest you try FetishMarket with its fantastic Find It feature which saves you having to manually type in every little thing you want to price check on.
Body drop junk loot and dropped normal items like armour etc will all be very similar in price within a zone but you will quickly learn what pays best. Of course the dropped armour/weapons pay well but they don't stack. If you are a high strength character who can carry a lot of weight you may not even know you can actually carry boxes instead of bags in your inven slots (now I will have tailors sending me death threats!) Boxes are often cheaper and of course bigger than bags
Upgrade to as many slots as you can asap!