iFixit posts repair guide for Retina MacBook Pro, estimates battery replacement at $500 - 9to5Mac
Amazon.com: A1417 Battery Only for (Mid 2012 & Early 2013) A1398 MacBook Pro - Replacement Battery for A1398 MacBook Pro 15-inch Retina (Mid 2012, Early 2013 Version) - EMC 2512 or 2673 [11.26V/99Wh] : Electronics
Original A1322 Replacement Battery for Apple MacBook Pro 13 inch A1278 2012 [65Wh/10.95V/6000mAh] - Newegg.com
How to replace a 13-inch MacBook Pro battery
Apple Exchanging Some 2012 and Early 2013 MacBook Pros Needing Battery Service With Newer Models [Updated] - MacRumors
Amazon.com: A1502 Replacement Laptop Battery for MacBook Pro Retina 13 Inch Late 2013 Mid 2014 Early 2015; MacBook Pro A1493 A1582 Battery EMC 2678 2875 2835 ME864 ME865 : Electronics
MacBook Pro 13" Retina Display Late 2012 Battery Replacement - iFixit Repair Guide
Free Batteries Replacement for MacBook Pro 2012-2013 | iGotOffer
MacBook Pro Battery Replacements - Macfixit Australia
MacBook Pro 13" Retina Display Late 2012 Battery Replacement - iFixit Repair Guide
MacBook Pro 13" Retina Display Late 2012 Battery Replacement - iFixit Repair Guide
Macbook Pro Retina Mid 2015 Battery Replacement - New Original Battery A1425 A1437 - Aliexpress
Amazon.com: A1382 Battery for MacBook Pro 15 inch A1286 Early 2011 Late 2011 Mid 2012 New Replacement Laptop Battery (7200mAh 10.95V/78.84Wh 25 Months Warranty) : Electronics