Gas prices are set to continue going down and might come in below $2 in some regions of the United States by as early as the end of this week.

According to Fox Business, the bargain prices are fueled by a decision from the Organization of the Petroleum Exporting Countries to keep oil production at current levels. Citing industry tracker GasBuddy.com, Fox Business said a $1.99-a-gallon price tag was most likely in Texas or South Carolina. That said, gasoline prices have already fallen well below $3 in most states.

Patrick DeHaan, a senior petroleum analyst at GasBuddy said he could not have foreseen such a deep decline "even a week ago."

"What a gift from OPEC," DeHaan added. "It's the perfect time of year for this to happen."

DeHaan is among many oil industry analysts who had expected OPEC to slash production amid a deep slide in oil prices. After it became known that the cartel had no intention to do so, prices for crude dropped even further, hitting a five-year low. For example, Brent oil fell below $68-a-barrel on Monday, according to Reuters; in July 2009, it had peaked around $145.

Some observers, though, warn that the market could see some "erratic price movements" as it goes through a "volatile adjustment phase," Reuters reports.

"The physical crude oil market is well supplied and that oversupply will last into the second quarter of next year," Olivier Jakob, an oil analyst at Petromatrix in Zug, Switzerland, said. "The market is trying to find some equilibrium level."

Drivers in the South and Midwest, meanwhile, are getting the biggest bang for their buck, Bloomberg noted. Many service stations there are only about 20 cents shy of the $2-a-gallon mark.

"We could see the cheapest 1 percent of stations get within a few pennies of $1.99 over the next two weeks," DeHaan told Bloomberg. "We'll see at least one station in the nation at $2 by Christmas. And that's not really a prediction at all. That's more like a certainty."