32GB (4x8GB) Crucial DDR4-2400T - $99.99 ($25 each)

32GB (4x8GB) Crucial CT8G4DFS8213 DDR4-2133 PC4-17000 288-Pin UDIMM Memory
https://rover.ebay.com/rover/1/711-53200-19255-0/1?mpre=https%3A%2F%2Fwww.ebay.com%2Fitm%2F32GB-4x8GB-Crucial-CT8G4DFS8213-DDR4-2133-PC4-17000-288-Pin-UDIMM-Memory%2F283759943369%3Fhash%3Ditem4211691ec9%3Ag%3AVwMAAOSwewJeMIuC&campid=5338535236&toolid=20008

$99.99 free shipping
This is a good deal especially if you are looking to outfit multiple HP 290s.