P.
We've used the "take and toss" straw cups for the past 2 years. They're in a 5 pack for like $3. Each comes with a plastic straw, which were quickly chewed, so I use disposable flex straws. They fit perfect and are cheap. They're not completely spill proof, but as long as it's not on it's side for 10 minutes, you only lose a few drops. And they are normal cups when you take the lid off, so he can always practice for a few minutes, then put the top back on when you can't handle the spills.