I have a stuff sack to hold all my little items and my circular needles. And I have this wonderfull roll-up-pouch, hand made (quilted) by my mother in law, that holds all my dpn in seperate pouches. If need-be that fits into my stuffsack as well.
inside the stuff sack I do have a few mini-zip-locks to hold my stitchmarkers, pointy needles and such.
My project bag contains enough of the yarn I am using to get me through the time I am around with it (like on a trip or when going somewhere). Sometimes I keep the extra yarn in a plastic bag inside so it does not get cought up with the ball I am using.
My project bag is just a type of canvas shopping bag with nice long handles that go over your shoulder easily and with a card-board bottom part that keeps the bag less tight.
At home, I just litter plastic bags and yarn bags (nice, really big canvassy ones I get at my yarn shop when I once again buy too much) around my office and my living room until I need to clean up
This makes it easy to just grab my current project. I can run the yarn out of that canvas bag and do that when I can not place it anywhere else (like mostly in the car or train).
So: I did never really spend money on my bags / containers. I just used what comes in handy.