A clear plastic lettuce container with lid, it's about a foot wide and good 8 inches across. This is deep enough to start almost anything and they can grow your sprouts in place until they are big enough to go in the garden.
I wound up using the smallest "seed starter" to hold onion skins for the compost pile. Since it seals tight it doesn't smell and thanks to being clear, you won't forget about it the next day.
Any container you use for starting seeds or cuttings should have a few holes in the bottom. Either use an ice pick (very 80's, I know) or a hammer and nail. You can also cut an X with a box cutter. The lid can also double as a saucer if you don't need a lid.