Sprint's struggle to compete against Verizon Wireless, AT&T, and T-Mobile US could be your gain.

The fourth-place mobile carrier is giving big discounts to customers who switch from the top three carriers. From this Friday until January 7, 2016, customers who switch to Sprint will get prices 50 percent lower than rate plans offered by the carrier they're switching from.

For example, customers switching from Verizon would choose from a separate rate card that has the same data allotments as Verizon, but at half the cost. Ditto for customers switching from AT&T or T-Mobile—under this deal, you have to choose from a rate card specific to the carrier you're switching from. One notable exception is that Sprint isn't offering a half-off version of T-Mobile's $95-per-month unlimited high-speed data plan, though Sprint already offers unlimited data for $70 a month.

There are some downsides, as Sprint said it will not match the other carriers' offers for data rollover. Sprint also isn't matching T-Mobile's unlimited music and video, but pointed out that it isn't restricting video quality like T-Mobile is.

Sprint's announcement said the half-off plans also don't include tethering, but Sprint told us that this is a mistake and that customers will be able to use their phones as mobile hotspots while drawing data from their allotments.

Here's a look at the prices, which will be available online, over the phone, and in Sprint stores:

Sprint

Sprint

Sprint

Customers can port between 1 and 10 lines and lock in the 50 percent pricing until January 8, 2018. Sprint CEO Marcelo Claure used the word "contract" to describe the two-year price guarantee in a call with reporters today, but a Sprint spokesperson told Ars that customers don't have to sign a contract to get the 50 percent off pricing.

Customers would be responsible for the cost of any device they get through Sprint if they end a service plan before paying the device off, but Sprint says the discount pricing is also available to customers who bring their own compatible device. If this works as we expect, the deal will be relatively risk-free for customers who are not under contract with their current carrier and can switch to Sprint using their current phone.

The fine print says an additional $25-per-month charge will apply when customers get subsidized phones instead of paying the full cost of the device.

Customers who switch from T-Mobile will continue to get unlimited 2G-speed data after they use their high-speed data allotments. Verizon and AT&T instead use hard caps with overage charges, and customers switching from those carriers will pay overages of ¢1.5 per megabyte while on the Sprint network.

This is similar to a deal Sprint offered last year, but in that case Sprint required customers to get a new phone in order to get the special pricing, cutting typical savings down to about 20 percent.

Claure said the new promotion is simpler than last year's and that he believes a lot of customers will choose to get more data instead of taking the full 50 percent discount.

Customers who don't bring their own phones can acquire a new device from Sprint through the carrier's various payment plans. Sprint is also reimbursing switching fees of up to $650 per line with an American Express Reward Card, but the reimbursement is only available for customers who turn in their current phone.

Switchers who aren't satisfied with Sprint service have 28 days to change their minds and return their new Sprint devices without paying a restocking fee. There's still a $36-per-line activation fee, which can only be refunded if customers return the device within three days of activation, and customers who leave early would be responsible for service charges for the time they use the Sprint network.

Although the 50 percent off switching prices aren't available to existing customers, Sprint has one offer for its current users. If they sign a new two-year contract, they'll get a free Alcatel Pixi 7 tablet with a year's worth of 1GB-per-month service.

The main thing keeping customers away from Sprint is the carrier's network quality. Although Sprint is too cash-strapped to participate in a major spectrum auction, it says it has used "cell site optimization, and our targeted deployment of LTE Advanced features like carrier aggregation and beamforming" to boost network speed and quality.

Claure said Sprint wants to do "something special to celebrate" the network improvements, hence the 50 percent discounts. Sprint aims to offer service good enough that customers will want to stay after the 50 percent discounts run out.

"After two years, the customer will have to make a choice," Claure said.