Starbucks will start selling $1 reusable plastic cups tomorrow to help cut down on paper throw-aways, reports USA Today. Customers who partake will get a 10-cent discount on coffee, meaning the plastic cup pays for itself after nine refills. Stores will offer a boiled-water rinse before refilling. Starbucks is rolling out the option nationwide after a successful test-market in the Northwest—the number of reusable cups increased by 26% over a month at the stores in the experiment. One environmentalist quoted in the story is skeptical it's enough to change behavior but welcomes it as a "step in the right direction."