Sprint is trying to climb out of the fourth place spot among major wireless carriers. To lure customers away from the other three major carriers, Sprint promised to cut their bills in half, and almost 500,000 customers decided to make the switch.

Sprint began the half-off promotion in November, promising to lower customers' bills by 50 percent if they switched from AT&T, Verizon or T-Mobile. The promotion paid off, with 491,000 customers signing up for Sprint in the fiscal third quarter of 2015, CNet reports.

The Price Is Right

Customers have historically considered Sprint's network to be lower quality than those offered by the other three carriers. Sprint has made improvements to its network and increased speeds, hoping to convince customers to switch, but the price cut is the main reason for Sprint's new subscribers.

Sprint's fiscal third quarter also included the addition of 501,000 postpaid subscribers. These are customers that carriers rely on because they tend to stick with the company and are willing to pay more. Postpaid subscribers pay their bills each month and often sign contracts of up to two years. Sprint added postpaid subscribers for just the second quarter in more than two years.

"The quarter marks a big step forward in our turnaround," CEO Marcelo Claure said at an investor conference today. 

Price Cuts Lead to Loss

With the price cuts, Sprint was forced to take a loss of $836 million, or 21 cents a share, on revenue of $8.11 billion. Analysts predicted a loss of 25 cents a share on revenue of $8.23 billion.

Those results are still an improvement for Sprint. Last year in the same period, the company reported a loss of $2.38 billion, or 60 cents a share. 

Poaching Goes Both Ways

While the postpaid business is improving for Sprint, the prepaid business saw 491,000 customers leave. Prepaid offers from AT&T's Cricket prepaid and T-Mobile's MetroPCS have attracted customers away from Sprint's prepaid service.

In late-day trading, Sprint shares were up about 20 percent to just over $3 per share on the news.