I figure that by useing my motorcycle last summer for short trips around town, putting about 2,000 miles on it in total, I saved over $200 by getting about 25mpg more on a motorcycle then my car could get, if a moped, scooter, or electric bicycle can do even better, and act as a useful vehicle by having a rack, or a back pack for carring things, then your theoretical savings is even more.
What do those scooter sell for retail? they cool... old school and simple. Have you seen the tw200 yamaha street legal dual purpose motorcycle. it is the best of all fat tires for offroad and good on road traction, fun like scooter 80mpg 70mph I bought a used 2003 for 2,400 check them out at www.tw200forum.com they are super cool
The Tomos mopeds, and scooter range in price from about $1,000 for the basic moped without turn signals, up to about $1,650 for the full decked out with crome scooter (the Revivel) with electric starter and front disk brake, I road one last summer and had to be carful to open the throttle slowly, and they are commen enough that you can get after market parts for them for racing, and of course regular parts for repairs, but there are people out there who do crose country road trips on these things.