Difference between 2013 and 2012 Prius Class 3

I am planning on buying a 2013 Prius and wanted to figure out if there is any difference at all between the 2012 and 2013. Whether it is cosmetic or just some general functionalities. Right now, I am haggling prices and am down to 25,250 with the solar package. I had someone beat it by 50 bucks and then they admitted it was a 2012. I just want to be able to tell the difference besides looking at an invoice.

Thanks,
Dean