Proud owner of the Galaxy S3 since August. I consider myself to be a power-user, so I'm on my phone pretty much always. Since that is the case, the battery in my phone lasts me all of about 4-5 hours. But I discovered a little trick today that I wasn't aware was possible, because Verizon isn't supposed to tell you about it:
If you have any kind of employer discount for Verizon through the company you work for, a lot of times you actually get a special "Accessory Discount" through them as well.
Well tonight, I went to the Verizon store with a friend and he was getting stuff taken care of with his phone. The sales rep asked as we were leaving "Can I get you guys any accessories or anything?" She showed me the portable battery packs (4000mAh) for $79.00. I went and saw they have a 9000mAh pack made specifically for Samsung Galaxy devices (Includes a standard 11-pin phone cable, as well as the 30-pin tablet cable) for $99.00. I was very interested, so I asked "What kind of deal can you cut me?" while not expecting more than a laugh. She actually looked me up, and gave me a 25% discount because of my line discount. I walked out paying $74.00 for a $100.00 portable battery pack. Now I can Ingress to my heart's content.
To those who don't know, the standard S3 batter is 2100mAh. This pack will charge my phone 4 times + before I have to recharge it.
TLDR; Asked for a deal, unexpectedly got one, and a GOOD one at that.
Just goes to show, it never hurts to ask.