I just bought a set of the chevy all weather floor mats. http://www.chevroletpartspeople.com/Sea ... stom+Vinyl
They were a little bit expensive, but I have to say, I really like them. The are a perfect fit and custom molded to the floor of the Aveo. They should do a good job of keeping the snow and salt off of the carpet.
I bought michelins from walmart. They were reasonable at $30 for the set, and did great when I had them in my passat. Hopefully they work good in the aveo to.
Lloyds makes some pretty sweet ones, with a couple different design concepts. I ordered the set that looks like those computer chair mats. For the 4 that are in the car, it's only $60 for those. For a deck mat, that's another $60. I love how these mats look too! I was gonna order the official GM ones, but it just came with the 4 main ones, and that was for $128!