or if u have a diesel make ur own fuel
but for must of us who have gas vehicles there are a few things u can do:
1. group your errands together, will save alot of fuel and miles on your vehicle
2. upgrade your exhaust and air intake on your vehicle. my 94 suburban is getting 17mpg city currently, and i havent even started on mods (my friend is getting 23 city in his 91 with a 350 and a 6inch lift)
3. buy something more fuel efficient, such as a motorcycle. or u could convert your dirtbike to a dirt/street bike with certain kits that contain turn signals, brake light. then u would need to file for a title (much easier in some states and impossible in others)