Buy mung beans--tiny dry beans, green and smaller than peas. I get mine in bulk at the health food store, but you might find them at Whole foods.
Put 3 tablespoons of seeds into a quart mason jar, and fill the jar half full of water and soak overnight. Drain the beans, and then rinse every day til the sprouts are the size you like--depending on the temp, you will have a jar full of nice big fresh bean sprouts in 3 or 4 days.
You can buy a strainer lid to fit a regular mason jar or mayo jar, but I just hold my hand over the top of the jar and let the water run thru my fingers.
You will see lots of green hulls as the beans sprout and split their skins. When you rinse the sprouts, those hulls will float to the top, and you can skim them off. I can't get them all out, like the commercial bean sprouts, but the ones that remain don't taste bad.