So, when you say big enough to carry a few things plus a little extra...Well, I guess the best way is to describe it because I've got this messenger bag I use for a LARP that I'ma use as an example with what I've managed to carry in it at one time: It's main pocket is big enough to hold like three standard (100 page) composition note books, then a back pocket that can hold like three of those half size composition notebooks, a pouch on either side that's big enough to fit a standard mobile (sure, there's lots of different kinds in various sizes, but the average of all that is what it fits), two small pouches on the front big enough for - say - carrying a standard roll of medical tape in each, two side by side pouches that are about as wide as the average hand but not a lot of give to put much more than maybe a pile of pens or folded paper, and to top it all off the flap/top to it has a pouch that's big enough for a composition notebook. 

Not saying she'd have all of that, but the entire bag, flat, doesn't look like it would hold that much - only the size (height, weight, and depth when flat) of a regular 3 subject notebook, but the capacity level is much larger than it appears. Does that seem to be too big, even though it is a relatively small bag? I would link up a picture, but I got it at a surplus army supply store in my area. 

(I won't even try to reason in this backpack I use, 'cause if everything's stored properly, I've fit two entire outfit changes, a handful of notebooks, some extra pens, two flashlights, 6 Nerf guns (the hand gun versions), a card game roughly the size of nine bicycle decks, and probably could fit more if I needed anything else. I know that's far too much capacity, but I wanted to check on the messenger bag, because that's roughly the size I was thinking for my female to have. *And yes, there are tons of nerdy in-game LARP jokes people make about my bags and how much I can carry.*)

But seriously, I will ask tons of questions if you don't stop me. Just ask Bee. I love minutia - if it wasn't a concept I would make love to it. ;D