This is something I've been interested in, the idea of having a marginal cost lifestyle. The main problem with it for physical items is that there is always a

This is something I've been interested in, the idea of having a marginal cost lifestyle. The main problem with it for physical items is that there is always a large upfront lump sum cost. A small hydroelectric system produces energy for practically free but costs a lot to build. It will last until your grandchildren are old though, it is a true investment.