When I was studying finances, I was shocked to learn that I spend between $400 and $500 a month in gasoline. I drive a 1997 Ford F-150 2 wheel-drive pick-up truck with approximately 190K miles. If you go to www.fueleconomy.gov one can learn the EPA estimates of fuel economy for a particular vehicle. In my case, city mileage is estimated to be 15 and highway is estimated to be 20, with an average of 17. I'm assuming the estimates are for a NEW vehicle and not one that is 13 years old with 190K miles on it. I can safely say that I've never had 20 mpg fuel economy. I've started saving fuel receipts and have started tracking mileage, so I'll have a better idea later what my truck is getting. I'm betting it's close to 15 mpg.
I work as a nurse and receive mileage reimbursement of 40 cents per mile. Depending on my work load, reimbursement runs from $160 to $350. I do a lot of personal driving to because my family lives out of state.
I think I'm in the market for another car. Let's say I can find a used one that gets 30 miles per gallon. The would cut my fuel expense in half, or maybe more if I could run the 87 octane vs. 89. My old truck won't run on the cheap stuff (pings, diesels, shakes, etc). I could keep the truck since it's paid for, and pick up a older, small used car for around $3000. Driving an older car would allow me to "save" my truck, which is more expensive to replace and hard to live without.
A $3000 car on a 24 month note would be approximately $140/month and for 36 months is approximately $100.
With a more fuel efficient car, fuel rates should be in the range of $200 to $250 with a car payment of $100 to $140. Best case scenario would be $300/month for fuel and car payment and worst case would be $390 for fuel and payment---still $10 less than what I spend on gasoline currently.
I'm thinking late 1990's small Honda or Toyota. I did have a Chevy Cavalier once that got 32 mpg. My ex had a Ford Festiva 1988 that got like 45 mpg.