Now that phone unlocking is legal once again, you might be wondering how it affects you, and what exactly you can do now. It's actually quite complicated, so here's a rundown of what's changed, and how you can take advantage of unlocking.

Millennials -- and in particular, young Latinos -- are ahead of the "digital curve" in the United States. That means Latinos are more likely to own a smartphone, use wireless Internet, and to plan on buying or upgrading their smartphone much faster than the general population. In fact, the most recent Nielsen survey on Latino digital consumers found that 49 percent said they were planning on replacing or upgrading their smartphone within the next six months.

But according to the latest Nielsen data available (via NHMC), Latinos on average also spend the most on monthly cellphone bills.

(Photo : Nielsen)

The high cellphone turnover, plus the need to lower monthly costs (who doesn't want a lower cellphone bill?) and phone unlocking becoming legal again means there are some options for using a "bring your own device" (BYOD) low-cost, and usually prepaid, wireless carrier. You can buy an unlocked device outright or unlock your current device if it suits you and find a low-cost option without the contracts. But even with unlocking once again being legal, there are technical issues to know about.

First thing's first. Your contract or installment plan has to be over and finished. Sorry, you need to have actually paid for your device in full either through fulfillment of your contract or by buying out the rest of your unpaid balance on installment plans before unlocking -- getting a sweet discounted phone and then cancelling your contract is not an option.

Not All Phones Will Work on All Networks

If you're thinking of unlocking your smartphone that you bought with a wireless contract, you need to take into consideration what network you're on. Not all phones work on all networks.

U.S. wireless carriers use one of two major standards for communication with your device: CDMA and GSM. Sprint and Verizon are CDMA-based, while T-Mobile and AT&T (and most of the rest of the world) use GSM. For the most part, phones bought on either side of this divide won't work on the other.

There are some exceptions, like some GSM phones that work on Verizon LTE data networks and some of Verizon's iPhones, which can work on GSM. But there are lots of variations and you don't want a phone that, for example, works on your new network for 4G data but can't make a call. CDMA. GSM. Figure out which side you're on before proceeding.

Unlocking Can Be A Pain

Again, another category where there's lots of variation and no set rules, but unlocking your device can take up to two days, according to the wireless industry's own lobbying group (via GigaOm). And because you're a customer who's leaving, your current wireless provider has no incentive to help you, and every incentive to make it a painful process.

Before you try, make sure you have the right information at the ready. This includes the main account holder's name and account number, the social security number associated with the account, the phone number of your device, and the IMEI number. The IMEI can be found either in the "about this device" section in your phone's settings, or barring that, usually underneath the battery cover.

Once that information is collected, here's how you unlock your phone for each major carrier.

AT&T: The company won't do it over the phone, so fill out the form here.

Verizon: Call support at 1-800-711-8300 and ask for a SIM unlock. Most Verizon phones have SIM slots, so you can try using them on GSM carriers. But, again, it very much depends on your device.

T-Mobile: Despite the publicity over its "unlocking app," it only currently works on the Samsung Galaxy Avant. You can unlock your device online here or call 611 on your phone to start the process.

Sprint: You're pretty much out of luck. Sprint's phones are made in a way that makes it technically very difficult to use on any other network, including Verizon. You can still try online with a customer service chat or by dialing * 2 on your device, though.

You might be better off going to a wireless/technology expert who's unaffiliated with a particular brand and paying for an unlock -- especially if you're in a hurry.

Major Carriers and Compatible Discount Wireless Brands

GigaOm's Kif Leswing put together an amazing list of prepaid and discount carriers that piggy-back off of the major four, so check out Kif's work for a thorough list of carrier options that includes some new data-only brands.

As you'll see, the main takeaway from this list is that if you're on a CDMA device, your options are much more complicated and limited than if you have a smartphone from AT&T or T-Mobile. Here are the major plans you might want to check out with details.

AT&T and T-Mobile Devices:

Straight Talk: Starts at $30 per month for 1,000 voice minutes, 1,000 texts, and 30MB of data.

T-Mobile: AT&T must be worried about this. The Simple Choice Plan for $50 per month gives you unlimited talk, text, and data (1GB of 4G LTE before throttling begins) with no contract.

H2O Wireless: Starts at $30 per month for unlimited voice minutes, texts, and 500MB data.

Ultra Mobile: Starts at $19 per month for 1,000 voice minutes, unlimited texts, and 100MB data.

Telcel America: Starts at $29 per month for unlimited nationwide minutes, 1,000 minutes international to landlines, 100 minutes to Mexico and Guatemala cell phones, 100 MB data, and unlimited texts (including international).

Verizon Devices:

Page Plus Cellular: At $30 per month, you get 1,200 minutes, 3,000 texts, and 500MB of data. However, data and call availability depends on your device.

Sprint Devices:

Virgin Mobile: Starts at $35 per month for 300 minutes, unlimited texts and data -- currently only supports Virgin-bought phones and does not support unlocking, but changes to those policies may happen before next February, since they're in violation of the CTIA unlocking agreement. We'll see, but in the meantime, Virgin does offer some of the deepest discounts on contract-free phones.

Boost Mobile: Starts at $40 per month for unlimited talk, text, and data (500MB only of un-throttled 3G/4G). Again, not BYOD or unlock-friendly yet, but that's probably going to change.

Multiple-Band Carriers:

There are a couple options from a U.S. subsidiary of Mexican billionaire Carlos Slim's America Movil called TracFone. TracFone is a company that offers various subsidiary flavors of service -- all prepaid -- and has been adding subscribers this year like gangbusters.

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