I have recently found these "Take & Toss Spill-Proof Cups" from the First Years that are AWESOME! They are made of a similar plastic as the disposable "Gladware" types of containers that are out there. They are marked "From 9 Months" and I am using them with my 2 year old twins. I LOVE them. They are easier to clean than valved sippy cups, and when they do not get clean enough, I don't feel bad at all tossing them in the recycle bin/trash. They are translucent so you can see how much liquid is in them, and for being disposable, they are surprisingly sturdy. My only complaint is that they do not (yet?) make larger cups for the larger toddler appetite. The ones I have found are all 6-7 oz cups. These are great for travel, when your access to a sink or dishwasher is limited. They are awesome for outside or at the playground. Dropped in the mud? No worries! On a recent trip, a Dad & his daughter approached, and the Dad struck up conversation. We offered them both a cup of soda, and my father poured each of them soda from a can into disposable picnic cups. While the girl took the soda, it was clear to me she was struggling with the weight and size of the cup. I remembered my disposable sippy cup stash in the car. When I poured her soda into her own disposable sippy cup, the child beamed with satisfaction - a cup she could easily manage! I beamed too - I didn't have to worry about retrieving the cup, or replacing a cup given away.
Whoever thought of these disposable sippy cups earns a big round of applause from me - I love them & so do my kids!
Theresa, A.K.A. Hooahmom, proud Mom of extraordinary twins Lawson & Grace