Amazon.com: OWC 8GB (2 x 4GB) PC19200 DDR4 2400MHz SO-DIMMs Memory Compatible with Mac Mini (Late 2018), 27" and 21.5" iMac (Mid 2017), and Compatible PCs (OWC2400DDR4S08P) : Everything Else
Apple iMac 27" All-In-One Computer, Intel Core i5, 8GB RAM, 1TB HD, Mac OS, Silver, ME088LL/A (Used) - Walmart.com
Crucial 8GB DDR4-2400 SODIMM Memory for Mac | CT8G4S24AM | Crucial.com
27 inch iMac with Retina 5k Display 2019 3.7GHz i5 1TB SSD 8GB RAM | Refurbished | Techable
8GB (2 x 4GB kit) OEM RAM Memory for Apple iMac Retina 5K 27 inch (Late 2014) Core i5 / i7 PC3-12800 DDR3-1600MHz 204-Pin SoDimm at Amazon.com