We recently switched my wife's cell phone provider from T-Mobile to Credo. I've had my eye on Credo for almost a year since I found out they donate money to good causes - 1% of charges plus they give you the option of rounding up your bill to the nearest $1/5/10 and donating the difference.
http://mobile.huddler.com/products/credo-mobile/reviews
The coverage is just as good as T-Mobile. The plan isn't quite as economical - $29.99/month gets you 200 minutes with Credo and 300 minutes with T-Mobile. However, since neither of us ever uses 200 minutes in a month, it makes no difference to us.
http://mobile.huddler.com/products/credo-mobile/reviews
By the sounds of things Credo will be a MVNO – Mobile Virtual Network Operator. Your contract is with Credo and you pay money to Credo, and when you turn your handset on it will say Credo, but Credo will buy wholesale capacity on Sprint Nextel’s network so some of your money will go to Sprint.
https://stupidevilbastard.com/2010/09/what-do-you-guys-know-about-credo-mobile/
What does “no contract for 30 days” mean? New members on a two-year service contract get 30 days to explore their new service with CREDO Mobile before the early termination fee goes into effect. All service charges and late/damaged equipment fees will apply during the first 30 days.
https://www.credomobile.com/coverage/
In fact, unlike any other phone company, we plant 100 trees for every ton of paper we use. Plus, we offer everything you’d expect from a first-rate carrier, and switching to our comprehensive service couldn’t be simpler. With CREDO Mobile, you get:*. Contract buyout credit (up to $200 each for a total of three lines) and your choice of phone. 25% off your monthly service fee for a year.
https://stupidevilbastard.com/2010/09/what-do-you-guys-know-about-credo-mobile/
Credo is what's called a MVNO, or a Mobile Virtual Network Operator - a term that defines service providers that license or lease a carrier's network and provide service on that network. Credo Mobile uses the Sprint network (perhaps that explains why they stay away from criticizing Sprint's corporate behavior). If you are a Credo Mobile customer, your network provider is Sprint, but your service and billing are handled by Credo Mobile. Most MVNOs give their customers a better value for their dollar, though they often include certain compromises. For example, many MVNO's save on cost by not providing any roaming coverage.
http://www.thepeoplesview.net/main/epeoplesview.net/2013/12/why-progressives-shouldnt-fall-for.html
List of United States mobile virtual network operators. Mobile virtual network operators (MVNOs) in the United States lease wireless telephone and data service from major carriers such as AT&T Mobility, Sprint Corporation, T-Mobile US, and Verizon Wireless, as well as the regional carrier the United States Cellular Corporation for resale. Contents.
https://en.wikipedia.org/wiki/List_of_United_States_mobile_virtual_network_operators
Here at CREDO Mobile, we’re always working on better. A better world for all of us. And better ways to keep you connected to it. Experience remarkable coverage on the nation’s largest and most dependable 4G LTE network.
https://www.credomobile.com/coverage/
You can exchange your CREDO Mobile device for another device within 30 days of your order date. You’ll be charged a $36 restocking fee for each device you exchange. If the new CREDO device has a higher value, you'll be charged the cost of the new device.
https://www.credomobile.com/coverage/
When AT&T acquired the company and merged it with Aio Wireless, Cricket transformed. Today, it runs on AT&T's network and has the benefit of coast-to-coast coverage. Cricket's place atop the lesser carriers was assured after its introduction to an unlimited data plan.
http://www.toptenreviews.com/mobile/phones/best-cell-phone-providers/cricket-review/
what network does credo use
Credo uses the Sprint network.