Cup Brands That Offer "Buy One, Donate One" Packages?

Forgive me if this has already been asked - I didn't see anything when searching.

I've noticed that both Ruby Cup and Femmecup offer buy one, donate one deals when purchasing from their websites. (You can purchase a cup for yourself, and pay for a second cup that the company will donate to charity.) Do any of you happen to know of other brands that have similar programs?

Thanks in advance!