Doing Good One T-Shirt at a Time Sevenly serves its causes through the sale of limited-edition T-shirts.

The premise is simple, but the results are impressive. Every week, Fullerton, Calif.-based Sevenly sells one new, original design on T-shirts and hoodies and donates $7 per sale to its charity of choice. When the week is up, so is the opportunity to buy that particular design. The limited window creates a sense of urgency to purchase, says Dale Partridge, who founded Sevenly with friend Aaron Chavez.

Shirts emblazoned with "Awaken our hearts to end hunger" raised more than $11,000 for Relief International, a nonprofit that responds to humanitarian crises. "Girls are not for sale" helped Girls Educational & Mentoring Services provide safe haven and education for victims of commercial sexual exploitation and domestic trafficking. And "It's time to listen / Care for autism" raised nearly $23,000 for Autism Speaks.

The numbers still surprise Partridge. When they launched their website in June 2011, he and Chavez figured they'd sell about 20 shirts, mostly to friends and family. They ended up selling more than 300 within 24 hours, and 860 the first week, raising more than $6,000 for International Justice Mission, a human-rights agency. Since then, sales of T-shirts and hoodies--priced at $22 and $35, respectively--have raked in more than $260,000 for various charities.