Welcome to the forum. You can call some local salvage yards for a left fender, but being a 'crash' part, they are hard to find 'used'. The most recent Mopar part # is 68079073AB. It fits 2011-2014 200s. The Dodge Avenger fender contour is slightly different.
If you do need to buy new, the best overall deal appears to be a pre-painted with free shipping fender on ebay here. Provide the seller with your paint code: