I bought an AT&T Samsung Galaxy S3 from someone on eBay a few months ago, and it has worked flawlessly on Consumer Cellular.
I have the Samsung-SGH-I747, Android 4.1.1.
Consumer Cellular Customer Service was hit or miss, just from the standpoint of technical expertise, since this isn't one of their in-house phones.
With the help of Consumer Cellular customer service, I was able to activate 4G data service by setting up a new Access Point Name (APN) on the phone. They did not, however know how to set up MMS for sending photos via text messages. Fortunately, default APN for the former AT&T connection still exists on the phone, so I found the proper "APN type" there, and copied it into my new APN.
I am very happy with Consumer Cellular, but no world is perfect. Over the 4th of July holiday, they must have done some kind of maintenance, because my phone locked up (very, very rare that this happens). I was able to get it working again by powering off, then back on. I did not remove the battery. I was at home, so I did not think to shut off wi-fi service in order to verify whether the 4G data network was working.
Today, I drove out of wi-fi range and discovered that I did not have 4G data. Pulling the battery for a minute did not fix it. I called Consumer Cellular and got the "we are experiencing high volume" message, gave it five minutes a couple of times, and went home to investigate.
When I shut off wi-fi and saw no 4G icon, I went to my APN settings and found that my Consumer Cellular APN was entirely gone, and the default former AT&T APN was green checked, as if it were the active APN. They can do that by remote. Damn! Fortunately, I kept good notes from the first time we set it up. Five minutes later, no call to the carrier needed, I had re-set up the APN, and 4G was up and running.
Note to self: Carry the following in wallet for future reference...
These are the APN settings for the Samsung Galaxy S3 with Consumer Cellular:
Name ConsumerCellular
APN: att.mvno
Proxy: 66.209.11.32
Port: 80
User name Not set
Password Not set
Server Not set
MMSC:
http://mmsc.cingular.com
MMS proxy: 66.209.11.32
MMS port: 80
MCC: 310
MNC: 410
Authentication type: PAP
APN type: default,mms,supl
APN protocol IPv4
Enable/disable APN green checked (enable)
Bearer unspecified
I noticed one change from my prior notes--a new field. Just under 'MCC,' they added 'MNC.' The 410 that used to be under MCC is now under 'MNC,' and 'MCC' is 310. And I am not techy enough to know what that means to the free world.
Be careful when typing in the APN type--the phone will try to insert spaces after the commas, but it should look just as shown, with no spaces.
Overall, I am extremely happy with my phone service at Consumer Cellular. My phone is 4G capable, but we live so far from the towers that I usually see only one or two bars. On a clear day, before the trees fill out for summer, we get a decent signal, and no dropped calls. In areas where the signal is stronger (more bars), I never see dropped calls.
I finally fixed our in-house weak signal problem by downloading an Android App called "Sparephone," which is set up in connection with a Google phone number of your choice. Sparephone is a godsend, in my book. I thought we were in for buying expensive antennae or boosters if we wanted to drop our land line, but with Spare-phone working over broadband wi-fi, and independently of the Consumer Cellular mobile network, we are assured of phone coverage in our house on cloudy days in July, as long as broadband is working. Sparephone settings let you disable it over 4G, so it will operate only with wi-fi. You wouldn't want to use it on the road because that would use up way too much data--saves you mobile minutes, but burns data.
Hope this works for you.
Cindy