My free iMac 27" (2009) core i7 2.8, 32GB, 1TB SSD High Sierra. only cost me a SSD and about an hour of time. : r/mac
Install memory in an iMac - Apple Support
Apple iMac 2009 A1312 MB952LL/A 27" C2D E7600 3.06GHz, 12GB RAM, 1TB HD Catalina 885909286300 | eBay
Memory Upgrades for Apple iMac 2009 - Up to 32GB
Apple iMac 27-Inch Late 2009 2.66GHz Intel Core i5, 1TB HDD, 12GB Memory A1312 | eBay
A-Tech 32GB (4 x 8GB) PC3-8500 DDR3 1066/1067 MHz RAM for iMac Late 2009 27- inch (Quad-Core i5/i7) | 204-Pin SODIMM Max Memory Upgrade Kit at Amazon.com
A-Tech 32GB (4 x 8GB) PC3-8500 DDR3 1066/1067 MHz RAM for iMac Late 2009 27- inch (Quad-Core i5/i7) | 204-Pin SODIMM Max Memory Upgrade Kit at Amazon.com
Apple iMac 27-Inch With 5K Retina Display (2017) Review | PCMag
Install memory in an iMac - Apple Support
iMac | 3.06 GHz Core 2 Duo | 27 Inch | Late 2009 - Techable.com
Late 2009, 27 inch iMac can use 32 GB of 1333 MHz RAM, beyond what Apple says - YouTube