Will this work on AT&T? GSM LTE?
Freedompop uses the Sprint network, so no it will not work.
Edit: sorry this is to answer the above post.
This is incorrect. While Freedompop does use the sprint network, this phone also has radios compatible with att and tmobile. You can use it on either, it should be unlocked. You can also wipe it and install stock android.
I have the SIII from freedompop and it IS locked. Also has been rooted with Freedompop’s garbage ROM. FYI By garbage I mean it is unreliable for battery performance (sometimes battery will last all day sometimes dead in two hours) Took it to Samsung authorized svc center they told me about the custom ROM, and said they could not touch it any further because it is now void from warranty. My advice would be to get a phone from another source and call Freedompop to activate it as I did with my Sprint TAB 3. Works great! and I can now also make and rec. calls from my tablet.
The question was about the Nexus 5, not the SIII. A freedompop SIII would be locked. All Nexus 5s are unlocked per Google poicy. Do a search, you can read about people using freedompop Nexus 5s on AT&T and T Mobile without having to take any steps to unlock it.
Also, I wouldn’t go to a carrier to ask them about custom ROMs on my phone, I’d just do it. Google is your friend to find out how.
 Item description includes the following:
The Nexus 5 is an unlocked phone and can be activated with other CDMA or GSM carriers, though you would need to get a new SIM card from the carrier of your choice.
It’s a great deal on a solid, though used, phone, even if you activate it on another service. Wish they’d had this offer a month ago when my Nexus 4 went kerflooey and I bought a refurb N5 for $160. I’m using it on T-Mobile’s web-only (or Walmart-only) $30 plan with 5GB data.
E.g. right now you can get a free SIM online by ordering with a plan (BYOD plan). Or you can get the SIM kit (for phone or tablet) for $3.99 with code SIMDEAL. N.B. for the $30 prepaid plan you have to activate on the web, not in the phone or with customer service.
I am already a freedompop user (I’m a big fan!). I just bought a new Nexus phone. Some questions:
It seems like I can’t register a new phone under an existing account. Can I?
What is the best way for me to proceed?
I did not go to the carrier to ask about the ROM, It never occurred to me it would be a custom ROM. I was having battery/charging issues.