Another waterfalls question

I'm considering adding a small waterfall to my pond. My yard has a natural
slope, so it shouldn't be too hard...the pre-fab fiberglass ones seem
easiest, but are they hard to attach rocks to cover the black color?
Also, how does it impact one's utility bill to add a small waterfall,
since you have to have something with the power to pull the water back up
the line to go over the falls?
Thanks,
Kirsten