Digi-Key has some Cypress 2M X 8, 1M X 16 SRAM for sale at about $5 a chip. There's a big "No Warranty" label on it. This is probably a drop-in for TechKnight's design.
https://www.digikey.com/product-detail/en/cypress-semiconductor-corp/CY62167G-45ZXI/2015-CY62167G-45ZXI-ND/9771526
https://www.digikey.com/product-detail/en/cypress-semiconductor-corp/CY62167G-45ZXI/2015-CY62167G-45ZXI-ND/9771526