One aspect that most people forget to get information for is the gas consumption of the car you are going to rent. If you are going to fill up with gas today at a certain price and tomorrow you will do the same but of course, at a different time and in a different location, you may see a drastical change in the gas station's price which may not make you happy, especially if the car you have rented has a high MPG. The agents at the auto rental company are not so intersted into the MPG of their cars, they are only going to advertise the best performances of each of their cars. If you mind to ask them about the MPG, they might not even know exactly and maybe some of them are even able to lie you about the exact number or they just don't remember it exactly. A good advice is to go to the internet and make a quick research on that certain car with the same engine, the year when it have been made the hp and so on.
The more information you can introduce into a MPG calculator, the more accuracy are the numbers.
A good option are the hybrid cars but when the gas prices go up, so are the requests of hybrid cars so at the same time when it's hard to find an available hybrid car, the prices are very spicy because of the high demand on the market. Sometimes it's not even worth it renting a hybrid car because the prices of renting it are so spicy that it will cover the money you save driving a hybrid car anyway. Also, in this kind of situation, the auto rental company managers take advantage on such a crisis, selling many hybrid cars or even all of their hybrid cars so that they make quick high profits, just because the demand is so high. That's why I always say that you must be informed about the MPG of each cars that a certain company has available for rental.
Saving gas money can also be made by using different kinds of methods for locating the cheapest gas stations and in some cases, some of them can make you some offers or if you are a coming back customer, you will also have some benfits. As an example, for about two years, I fill from the same small isolated gas station in the town which at the same time, has the lowest prices in the city. Even better, during Sundays they have lower prices and I also won twice 5 liters of gas. If you do some little research, you will also find some smartphone apps that will give you tips depending on which car you own on how to save money on gasoline and also the exact location of gas offers in your town.
You should never ignore the gas prices aspect because if you aresmart enough, you will always have to win. You must also make sure you know how to use it and if you don't, read the manual or ask the agent to teach you so you won't end up using the phone while driving. Another great thing on some rental car firms is that they have available GPS devices that can be activated by voice.