Apple iMac MK452LL/A Late 2015 21.5inch Silver I7-5775R 3.3GHz 16GB 1TB HDD (Scratch and Dent) - Walmart.com
Used Apple A Grade Desktop Computer iMac 27-inch (Retina 5K) 3.3GHZ Quad Core i5 (Late 2015) MK482LL/A 16 GB 1 TB HDD 5120 x 2880 Display Sierra 10.12 Includes Keyboard and Mouse - Walmart.com
How to Add An SSD To The 27" iMac (Late 2015) - iFixit Repair Guide
How to Add An SSD To The 27" iMac (Late 2015) - iFixit Repair Guide
Apple iMac 27" Retina 5K Late 2015-Monterey, 1TB HDD, Intel i5 6th Gen, 16GB RAM | eBay