Hybrids come in different flavors, ranging from basic MPG savings all the way up to no gas-consuming electric vehicles (EVs).

Mild Hybrid

A "mild hybrid" was popular in the early 2000's for manufacturers who wanted to slap a "hybrid" sticker on their cars, but didn't want to go crazy with the technology. These vehicles typically have a "stop-start" mechanism which turns off the engine when the car isn't moving in an effort to save gas. Fuel savings are usually pretty minimal, but they do have an effect.

Pure Hybrid

A pure or full hybrid are very fuel efficient. They use the same technologies as mild hybrids and can navigate between multiple modes of operation -- run purely on gas for more power, a mix of gas and electric for everyday use, and pure electric for cruising.

Plug-in Hybrid (PHEV)

A plug-in hybrid (PHEV) typically have larger batteries than pure hybrids and can be plugged into an outlet to increase their on-board supply of electricity.