Hey Mr. Green, 

I'm in my senior year of college. I live off campus, and we throw a lot of parties. What appalls me is the amount of nonrecyclable plastic cups we go through. If we use 100 cups per party and have 12 parties a year, that's 1,200 cups we're wasting. Are there any reusable plastic cups that are cheap and environmentally friendly? 

--Dan in Titusville, New Jersey

The mere thought of heaps of disposable cups, replete with congealing backwash and reconnoitering insects, can spur even the most environmentally indifferent into action. I recommend rigid plastic tumblers, in part because they provide a nice example of how helping the environment can also save you money.

I could have taken the easy path and recommended biodegradable cups made from corn, potatoes, or other "renewable" substances, but I haven't found convincing evidence that biodegradables are significantly better for the environment than regular plastic. And glassware is neither a safe nor a cheap solution.

Rigid plastic tumblers are sufficiently durable for long-term reuse. Since no self-respecting college party host would countenance vessels smaller than 16 ounces, I assume that's your current choice. You can get nondisposable plastic tumblers at restaurant-supply stores or online for $1.50 or less each--$150 for the 100 you need. Of course, you have to factor in additional funds to cover theft, stomping, and inadvertent melting--not to mention the time and water needed to wash them.

But if you're spending $240 annually for the throwaways, even if you use the sturdier cups for only one year, they're a better investment--for your pocketbook and the planet.