One peculiar thing that happens when people find out I am interested in saving money is that they tell me about the things that they do to save money too. It becomes a sort of contest to see who is the most frugal. I always win because no one else lives in an RV and depends on rainwater :) but I like to hear what things other people do and what they would like to do.
Many people would like to use solar energy more if it wasn't so expensive. The return on investment for a whole house system seems to be stuck at 20 years. Until they come up with a cheaper technology not many people are going to go for that. I know a few people who built strawbale houses and have water running through their concrete floors for heat. Supposedly this is a very cost effective method of heating. A neighbor just put up a windmill. I haven't had a chance to ask him about it yet but it looks cool!
On a smaller scale, a few people I know use their laundry water for their landscape including me. Most people have drip systems for irrigation. It saves water and keeps the water close to the plants. All the new houses have drip systems installed as standard now. Using rocks for the front yard instead of grass is standard practice also. That took some getting used to when I first moved here from California (home of the manicured lawn with sprinklers watering the sidewalks).
My mother is even re-analysing where her money is going and trying to plug some money holes. She told me she put quilts over the windows and blocked off the gaps under the doors to stop the drafts this winter. She uses space heaters in the rooms that are used more and keeps the temperature for the rest of the house low. She also wears about 4 layers of clothes including long underwear. Hopefully this will help her save some money on propane this year.
So, what frugal thing that you do saves you the most money? I can always use more ideas!