I bought a large mixed container of beads at our craft store for about $4. Lulu loves sorting through them and picking out her favorite beads...which we put in a recycled spice jar. The other beads she makes bracelets with or just likes to sort through them. We store the beads in a container I got at the dollar store. It is important when working with beads that you use a tray with sides to keep the runaway beads to a minimum.
Having specific standby activities available and organized (i.e. beads, lentil tray, water play, playdough, puzzles, painting...) allows your child to to ask for a particular activity during down time. It also allows you to give your child choices when they are looking for something to do. It also helps to have a designated spot for messy activities, especially if you have younger children. Lulu will come in sit herself at the table and ask to do "beads please" or "lentil tray please."