Oh, I have. Ironically, the MAC counter I most frequent is Saks Fifth Avenue in NYC. It's 3 blocks away from school, and I have a very nice MA there that I go to. The problem is, it's really busy there all the time. So I wouldn't want to ask her to make me a sample.
When I'm in school, I go to the counter every 2 weeks or so and spend around 40-50 bucks.
Sometimes I go to Bendel's but I don't know any of the MAs by name over there.