I love, love, love Softcups --
http://www.webvitamins.com/product.aspx?id=47597&utm_medium=shoppingengine&utm_source=googlebase&utm_campaign=acquisitions&gclid=CjwKEAjw9uypBRD5pMDYtsKxvXcSJACcb9AYmpMU8qVWp6gMKd4Xwcg2DUFnTTCBtVaalpNrG0HKQBoCCVnw_wcB
I use the disposable version because I haven't gotten up enough confidence to clean them out and feel comfortable with the safety of it yet, but they make both disposable and reusable (and I guess they are basically the same).
Even using disposables, I use WAY less than I would if I were using pads or tampons. You can wear them for 12 hours, and they are super comfortable and super clean. I feel like I'm not wearing anything (whereas tampons have always left me still aware that I'm wearing something). There's almost no mess except when I take it out (which isn't a big issue and goes into the toilet, not on me), so there's much less smell (not to be gross, but it can stink!).
You can apparently even have sex while wearing one if you want (though I've never tried).
Anyway, I think most of the reusable cups are probably similar. If you want to start off with a test and see what it's like using something other than a tampon or pad, the disposable Softcups might be a good choice to try for a month to see what you think (they are cheaper than some of the long-term-use products).
I just wanted to chime in because even if you aren't going "green" (which I applaud you for), I still strongly recommend the cups over tampons or pads!