There's a term used which may apply to such a lifestyle: freeganism.
Freeganism is a practice and ideology of limited participation in the conventional economy and minimal consumption of resources, particularly through recovering wasted goods like food. The word "freegan" is a portmanteau of "free" and "vegan". While vegans might avoid buying animal products as an act of protest against animal exploitation, freegans—at least in theory—avoid buying anything as an act of protest against the food system in general.
Freeganism is often presented as synonymous with "dumpster diving" for discarded food, although freegans are distinguished by their association with an anti-consumerist and anti-capitalist ideology and their engagement in a wider range of alternative living strategies, such as voluntary unemployment, squatting abandoned buildings, and "guerilla gardening" in unoccupied city parks.
Freegans have organized themselves a bit, and have a website: freegan.info: strategies for sustainable living beyond capitalism. On this website you could find more information about strategies and even meetings of local like-minded individuals.
However, as @Tim points out in the comments, while the freegan ethos relates to a fundamental rejection of capitalism, your participation in the economy as a worker means you aren't (yet?) a freegan.