The owner's manual recommends against towing with a Prius C, but I don't mind voiding my warranty after doing a bit of homework. So here's what I've got:
It's a 2012 Prius C with an aftermarket Class I trailer hitch, towing a Harbor Freight 4'x8' folding utility trailer. This setup is rated to haul 800lb in the trailer, but I haven't had any cargo that heavy yet. I've used the trailer to move house, buy a couch, move appliances, and make trips to the hardware store, and I'm very happy with it.
It's kind of funny to watch a compact hatchback towing a not-so-compact trailer. Fully loaded, the trailer is just as long, wide, and tall as the Prius. :-P But the car weighs 2500lb, it's surefooted, and it has brakes to spare. I struggled to get 40mpg while towing, but the great thing about a trailer is it can be detached when not in use.
Just one more reason to get a Yaris instead of a Tacoma, if what you do is occasional hauling.