Fender rust and aftermarket fender flares

I had trouble finding any info here on this subject but I'm sure it's something that many of you have experienced. Rust above your fenders. They make the larger flares but there are so many out there on the market, that it's difficult to decide which ones to get. They range in price from $60 all the way up to $500. In my research I've concluded that in order to paint them to match a vehicle, they should be smooth instead of the textured ones. Does anyone have experience with any of these, specifically?

Aside from the new flares, how does one tackle the rust that's present? It seems that most of the flares (both new and old) are bolted or riveted on, so I'm somewhat curious as to what's beneath my current (factory) flares (I have the slimmer chrome ones).

Any advice on either aspect would be appreciated