I've been using these same beads and soap dishes for the past 7 or 8 years. They have worked great. Everything bought in Walmart, total cost per unit around $2.00. Envelope of beads, enough for probably 10 units was $3.00, soap dishes were a buck, six sponges were a couple bucks. Of course, costs could be more now since I bought everything 7 - 8 years ago. You do want to use sponges that are antimicrobial, they don't seem to grow mildew. Only thing you really need to do is drill some holes in the soap dish.
