I'd like to add to the list of waste-reducing menstrual methods, that many women who use an IUD (intrauterine device) often stop having periods entirely, contributing significantly to sanity in more ways than one.  

The Mirena IUD, for instance, prevents pregnancy through a combination of ultra-low hormone levels released through the device and preventing lining from accumulating on the wall of the uterus, which is the same reason periods happen less frequently or not at all. Preventing periods, of course, prevents the need for feminine products. And this method is truly worry-free. Kaiser paid for mine, and I love it.

Love the idea of the moon cup, however, be cautioned it may not work for everyone.  I was a customer that wanted more info (the product was excruciating to remove), so I repeatedly contacted the company (phone and email) and was met by an unhelpful phone staff and no one responding to my emails.  Furthermore, I returned the item for a "guaranteed refund" 5 months ago and am still waiting for it. I am deeply disappointed in the Keeper Inc.'s customer service, so beware if you are going to do business with them.