I have used a black plastic barefoot willies cupholder on my Ultra and RG for about 4 years. They are a lot cheaper than most, but I did have to replace the platic clamp with something I already had in the garage. I use it for drinks when taking long trips, but have found it's a great place to put my gloves when I don't otherwise need it.
I have one like this I use it often, you should see the looks I get running down the interstate drinking a cup of coffee.
Hers one heads up warning on the holders.
The one I have use a rubber gromet to secure holder to mount. They are easly removed from the mount .
Make darn sure you use the gromet. your may find yourself picking up you coffe cup and the holder comes with it then falls free of the cup on to your fuel tank and or bounce down the road.
Please don't ask how i know.