I became friends with a group of secular homeschooling moms when I started teaching my son. I remembered feeling relieved when I finally met people who didn't spend tons of money on toys, expensive activities, or cable television. They all have frugal, environmentally-conscious lifestyles. I'm inspired by their determination not to waste anything. When we get together for playdates, I see mason jars as the top containers of choice for every kind of food or beverage. I feel guilty pulling out the tupperware. They mostly shop at thrift stores for clothes--I'm not the best with this, I usually go through the clearance section at a retail shop. The only area I am probably more mustachian than they are is in gasoline consumption (many live outside of town), but they kick my butt when it comes to growing food in a garden. All of our kids are involved in paid activities, but the activities are reasonably priced and helpful for our children's educations. We take advantage of the free experiences offered through the local university. Everytime I go to the public library, I run into one of them. None of them own cable. I've gotten a little too comfortable probably. It's a shock when I return to my hometown for a visit or meet up with conventional friends where I live now, but it's really nice to feel like I'm not fighting against the machine all of the time.
I'm also inspired by a few families and teachers at my daughter's charter school. They bike to school quite often and strive for voluntary simplicity in many areas of their lives.
I don't really ever talk about finances with any of these people, though. I don't think that they are "mustachian" in the sense of saving lots of money. They could be. I do know that many of my homeschooling friends eat only organic foods (or the healthiest alternative if organic isn't available), so the food that they are not growing themselves is pretty expensive. We only buy about 1/3 organic. I admire their convictions, though. They are really inspirational.