The Sephora Beauty Insider program is awesome. I don't know if it's only for the US, but you get a card (it's free, too). For every dollar you spend at Sephora, you get points added top your "Beauty Bank." When you reach a certain point in your Beauty Bank, you get free, exclusive samples. I got a sample of Clinique mascara today, and I've received other good stuff that way as well. They're decent sized samples and are always really cool things that they don't normally offer as samples.

They also occasionally will do promos like the Stila shadows early.