Amazon.com: Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3 1333MHz PC3-10600 for Mac Book Pro (Early/Late 2011 13/15/17 inch), iMac (Mid 2010, Mid/Late 2011 21.5/27 inch), Mac Mini(Mid 2011) RAM Upgrade : Electronics
GetUSCart- Timetec Hynix IC 8GB KIT(2x4GB) Compatible for Apple DDR3 1333MHz PC3-10600 for MacBook Pro (Early/Late 2011 13/15/17 inch), iMac (Mid 2010, Mid/Late 2011 21.5/27 inch), Mac Mini(Mid 2011) RAM Upgrade
Today picked up a $20 2011 iMac 27” with working gpu too! : r/mac
NEMIX RAM 32GB (4x8GB Upgrade) DDR3-1333 PC3-10600 204-Pin SODIMM Memory for Apple MacBook Pro Early/Late 2011, iMac Mid 2010 27 inch 4-Core, iMac Mid 2011 21.5/27”, Mac Mini Mid 2011 at Amazon.com
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com