I had 4 on the bike at one point, yes 4. Don't ask.
This is a plain $.99 cup holder from any gas station, fits over the clutch reservoir, just put in two holes and zip tie it on. Have used this setup on mutliple bikes without an issue.
On the left is a standard handlebar mounted bicycle bottle cage. These are just a few bucks shipped on eBay, in the center is a handlebar mounted cup holder, the difference between a cup holder and a bottle cage is that the cup holder is tapered to accept cups. Must have for coffee. On the right I had an L bracket on the handlebar mounted mirror stem which had a Bell expandocage for large bottles. Note it's not pictured.