I'm becoming a bit of a broken record in threads like these, but my advice is always the same.
Next time you go out on a short backpacking trip, simply wear the comfortable pair of running shoes you undoubtedly already own instead of wearing your traditional boots.
You get to spend $0, and in the process, learn what it's like to backpack with lighter, more breathable shoes.
I find the only way to that anyone makes the switch from traditional, heavy boots, to lightweight running shoes is to just try it out. Seeing is believing. Try it out in a low stakes situation and you will get to see what it's like first hand.
There is very little that is special about "trail runners" versus your run-of-the-mill running shoes. Just wear whatever is comfortable and let the rest of us BPL junkies with no time to go out ourselves debate endlessly about merits of one trail runner versus another. :)