I have several different trays to use when beading, but these:
are by far my favorite because I use seed bead most of the time. Occasionally, some beads might get knocked from one section to another, but overall, they are very handy. You can use them to dole out just enough beads for the project you're working on, and you can just cover the sections up if you need to take break to make dinner before you've finished working on a project. Then, you just go back and pop the lid back off.
Also, see their spouts?
Those are very nice for putting the beads back in their larger containers when the project's done. I can just seal off all the other colors and pour out the ones I don't need.
I've had these for years, so I no longer remember where I bought them. Maybe Walmart. Maybe Hobby Lobby. In either case, I'm going to buy myself another, because right now, I have three projects going at once, and the 12 spots I have for different colors now isn't quite enough.