With my budget being rather small, but desperate to get my droid finished, I followed the advice of a couple R2 Builders and made my own out of left-over styrene. It took some patience, but it paid off, and I'm quite happy with them. In fact, I don't think aluminum coin returns would have fit in my droid. The styrene versions seem quite at home among the styrene skins I made.
I thought I had taken more pictures of them, but I don't seem to have more than this. Here are my coin returns prior to priming and painting: