http://wiki.project1999.com/Weight-reducing_Bags
Large soiled bag is a great purchase after you've gotten 5/55 rings and a great weapon, since you'll be carrying stacks of bandages and maybe ammo if they fix skipping stone.
The summoned ones should be free from a passing mage. I would empty them in town before you corpse camp them until you're used to it. If you don't wanna do the summoned bags, your wife can just master loot for you both.