Although the studies are still inconclusive you might want to consider using automotive fuel saving devices to save you money at the gas pump.The following products have been tested by the Environmental Protection Agency (EPA):
Air Bleed Devices - These types of devices are designed to bleed air into the carburetor and are generally installed in your vehicle in the Positive Crankcase Ventilation line.
Fuel Max
Aquablast Wyman Valve Air Bleed
Gas Saving Device
Grancor Air Computer
Vapor Bleed Devices - These devices are related to the air bleed device but in this case induced air is forced through a container that contains a mixture of water and antifreeze. This device is usually installed in the engine compartment.
Econo-Mist Vacuum Vapor Injection System
Mark II Vapor Injection System
Turbo Vapor Injection System
Atomized Vapor Injector
The above automotive fuel saving devices may or may not help you save in your gas consumption and cost but if you are seriously looking for a way to save money you may want to consider trying one or two of the products.