Set of 4 Melmac Avocado Green Cups
These are melamine cups from the 1960s or, maybe early 1970s. Melamine ware, aka Melmac or Texasware, was popular in the 1960s. These are in avocado green, which was popular in the late 1960s and early 1970s.
These are for sale on Ebay or directly from me.