I use either the 5oz paper Dixie(tm) cups, or the 18oz Solo(tm) plastic cups that I buy in bulk. I slice a few drain holes in the bottom, and they are dirt cheap. They are also standard size for the flats that I have built for them.
/johnny
I like the 5 oz dixie cups. Biodegradable a little quicker than plastic, I think. Any way, they don’t take up as much space on my little table.