How to get camber on the Prius C ?

Front is a mcpherson strut, so the normal "crash bolt" method will get you some. I don't really recommend them, but the option is there. When I built the rear coil overs for my 84 Camry I used factory eccentric bolts from a Subaru and made the strut housing compatible with them.
more info

For the rear you can get a little bit extra by picking up adjustment shims from an auto parts store. They are plastic disks that bolt between the wheel bearing and hub designed to fix a bent rear axle during an alignment. Again you won't get a lot out of them. There is a guy that makes sets of angled spares out of aluminum for the Scion xB, which shares the wheel bearing with the Yaris and Prius C. I have a set of 2.5 degree spaces from him that I'm not going to use if you want them let me know and I'll figure out what I paid for them and come up with a fare price from there. The final trick is the "washer trick" and you'll find details on the Yaris boards for this. Again I don't recommend this method even though it's exactly what I did to get the setting I needed on the rear of my car. I don't think you'll get where you need to be doing that though.

 

There was a guy in japan that did a custom fiber glass widebody on the c. It’s sick but he is running about the same wheel set up. Just to clear it. I doubt you will wanna go to that far to run wide wheels but it’s something different