I use see-thru colored ArtBins that i bought at Jo-anns. they hold up to 12 inch blocks nicely and they have a carrying handle. I got different colors so I can tell what WIP is in there as well. I got them for about $8-$9 on sale or with a 50% off coupon.. I love them.. Keeps me organized..
Also I saw a post on here about how someone uses the clear containers they get with food- clear fruit containers, See thru to-go containers, etc.. A good way to recycle and get free storage containers..