Why don't they tell us this?
Important requirements for cups:
they must be heat stable enough to take the sudden shock of near boiling water
They should be clear so you can see the demarcation between the layer of grounds and liquid. This is so you can get a consistent fill.
It needs to hold 5 ounces of water preferably with a little neck for holding aroma together
wide enough to fit nose and spoon in at the same time
Available
inexpensive
I found the solution.
Ball? Collection Elite? Platinum Wide Mouth Half Pint (8 oz) Jars
I just bought 4 for under $4 at Walmart. Any half pint wide mouth jars will do, but I like that 5 ounces comes right to the bottom of the neck holding the aroma concentrated as you sniff.
My next job was to find cupping spoons.
I guess I am just dumb, because I didn't realize I was looking for "gumbo spoons"! they are widely available once you know the arcane terminology.