Gas prices have been on the rise over the last several weeks, and some experts predict the increases won't stop any time soon. With the average gallon of gas costing close to $4, anybody considering buying a used car may want to heavily weigh the importance of fuel-economy on their next purchase, Kelley Blue Book (KBB) advises.

The national average price currently stands at $3.59 a gallon and buying a fuel-efficient used car may be a great way to save money over the next several months, as gas prices could reach near-record levels. Analysts at KBB say an increase of $1 per gallon could cost consumers who drive a car that gets 20 miles-per-gallon an average of $11.50 each week. Though it might not seem like a lot, it could make a big difference.

"While in today's economic environment many families are on an extremely tight budget and $11.50 per week may be enough to break the bank," said Alec Gutierrez, the senior market analyst of automotive insights for KBB.

Of course, there are some cars that are better choices than others for people looking to get behind the wheel of a fuel-efficient car. For instance, the Toyota Camry has been a longtime favorite and its new hybrid model gets an impressive 41 miles per gallon on the highway. Other good options include a used Ford Fiesta or Hyundai Accent, which not only provide optimal fuel-efficiency but also are affordable options.

Those looking for a small used car might want to head to New Jersey State Auto Auction. The dealership offers shoppers a wide variety of makes and models at affordable prices, and with guaranteed credit approval everyone can walk out with a new ride.