I have a set of 3 plastic bins that snap to each other in a stack with a handle on the top lid. The top bin has dividers; that's where my needles, templates, pincushion, Thread Heaven, etc. goes. Next bin down is where I put all my fabric scraps and flowers-in-progress, and bottom bin is large enough to hold about a dozen finished flowers nice and flat (which is way more than I ever get done on a single trip) plus my small scissors. When the bins snap together, the bottom of each bin is the lid of the next, so they stay in a sort of tower that's really easy to carry around. I keep those supplies in that kit whether I'm traveling or not - it "travels" from the sewing room to the couch when I'm working on them, and then "travels" right back into the cupboard when I'm done!
I think I bought them at either Target or Joann's; it comes as a single unit.