MetroPCS may hand the major carriers some competition, with its new 4G LTE plan for budget-conscious consumers.

Available as a promotion, the carrier's new 4G LTE plan provides unlimited talk, texting, and 4G LTE data for $55 a month for a single line. Families can join in by paying $50 a month for second, third, and fourth lines. Though the deal is being offered as a promotion, the expiration date is open-ended.

MetroPCS President Thomas Keys told CNET that the end of the promotion will depend on the adoption rate by consumers. "We didn't want to set an artificial timeline," he explained.

Beyond the eventual expiration date, customers can hang onto the unlimited plan and $55 price tag for as long as they stick with MetroPCS.

The company claims that individual subscribers can save up to $2,200 over the course of a two-year contract when compared with rival carriers. Keys also told CNET that the unlimited plan "has no strings."

To take advantage of the high-speed service, MetroPCS subscribers can pick up an LG Motion 4G phone for $149. Equipped with Android 4.0 Ice Cream Sandwich, the new LG Motion offers a 3.5-inch touchscreen, a 1.2GHz dual-core processor, a 5-megapixel camera, and a 1,080-pixel HD video recorder.

To kick off the launch of the new phone and plan, MetroPCS is offering consumers a rebate on the second of any two 4G LTE smartphones purchased. The rebate offer is good for the LG Motion 4G as well as other 4G smartphones offered by the carrier.

Consumers eyeing the new plan or the new phone can visit a MetroPCS store or hop onto the company's Web site later this week.