I've noticed that a lot of kits in the Ultimate Equipment Guide list "a box" or "this box" or "in this box." Problem is, all the equipment listed in those descriptions can be found throughout the UEG except the boxes that are listed.
I've found a solution to this problem, basing the prices, weight and carrying capacity off of chests (where a Large box = Tiny Chest)
Size / Weight / Price / Cubic Feet / Carrying Cap.
S / 3 lbs / 2 sp / 1/10 Cubic Foot / 10 lbs.
M / 6 lbs / 5 sp / 1/2 Cubic Foot / 30 lbs.
L / 12 lbs / 1 gp / 1 Cubic Foot / 60 lbs.