I am currently wear-testing a shoe that I think retails somewhere around $120. I have previously wear-tested a slightly altered version of the same model as well as its prior incarnation. I believe it is the model that replaced the shoe that corina referenced. This one, by far, is the best of the ones I have tried. They removed a hunk of plastic from the medial side of the shoe and it is noticeably less clunky. Not that I would endorse the shoe, though it works well enough and the design is at least improving. I wore the Asics rival to this shoe, the Kayano in its first few editions, years ago when I was in college. A teammate from Kenya was puzzled that I would train in such a heavy shoe. I had some odd ideas about running shoes at that time.
Also somewhat of a “road hog,” especially in winter, I too have found that regular running shoes work just fine for the majority of trail running. I do have some purpose-built trail shoes, but those are more for running up and down mountains where sharp rocks (and the desire to protect the soles from them) and steep slopes would be more of an issue. I have found that most purpose-built trail shoes seem to be over-built and thus tend towards the lightest ones available that still have a tough sole with good lugs.
It is sort of odd, as much as I may know about running shoes I really do not dwell much on the details and truthfully I consider them as little more than slabs of rubber and foam to grind into the ground and erode away. If I am training right then they should not last me more than about 100 runs, anyway. They end up used up and gone so quickly that it renders thinking too much and/or spending too much on them make little sense at all.
Do any of you donate your shoes once their running life is used up for you?