US Mint Medal Availability

I was looking at the Benjamin Franklin Bronze Medal on usmint.gov, and I'm thinking about getting one as a gift for a friend or maybe even for myself. I've never bought a medal from the US Mint though, and I was wondering if these are available at least year-long, or have a more limited availability like some coins. Will I be able to order one a few months from now, or will it be gone from usmint.gov by that time?

Also, a silly question, but what does the mint mean by 3"? is this what the medal measures across, diagonally, it's circumference, or what? Is there a comparative-size photo of it I can see someplace?