Robert Riley's XR3 could be the shape of things to come; it is a compact 3wheeled hybrid, which can reach 125mpg on biodiesel and 225mpg in hybrid mode. The super efficient engine is not going to come cheap, but as a relief, you could build one yourself if you are CAD savvy. The designer has adopted the IKEA route of DIY car assembly; there is a DVD in the package, which will fill in any garage builder's time. The car weighs just around 1480 pounds and has a top speed of 80mph; the Li-ion battery could take the car 40miles on a full charge. The car recharges via conventional power outlets.

Buying the XR3 outright will cost you $25,000 however; the costs could be brought down by making smart choices to upto $7,500. There are other techniques, which could convert your current vehicle into a cheap hybrid without the fuss.

Source