Dumb forriner question

For any Americans reading, how does one buy postage stamps in this country? I ask because last time I tried this I got a lot of dodgy looks, some homophobic abuse^* and no stamps.

* I think based on the erroneous assumption that blackherring and I were a couple, rather than the fact that I was trying to buy stamps. I reckon that since I am in fact bi, if people are going to hate gay people I'm fairly deserving. But it was a bit mean on blackherring who is in fact a virtuous married woman.

Contentment

Today, I sat in Central Park eating a ginormous bagel, and considered that my life is very good just now.