I get my bags from the Dollar Store. They have freezer zip-lock bags in the larger sizes in the houseware section and they have smaller zip-locks in the craft aisle. I use a hole punch to put in a hanging hole above the zipper part of the top plastic. They also carry really big zip-locks for WIP storage.
The white boards that some of the ladies use for fabric are comic book boards (as previously mentioned), white foam-core boards they cut themselves or recycled cardboard boards. There is an excellent tutorial on this board by Alasasunshine(I think) on how to make your boards yourself.