Here's what I found today by stopping at the recycling bin in the Wal-Mart parking lot in Mt. Vernon. I was probably only there a total of 5 minutes and was able to find 13 complete inserts by just shuffling through the top layer of papers. Maybe you should give it a try...you'll never know what you'll find. :)
If you do decide to give it a try you should know that the weekends or Mondays are the best day to look for inserts because that's when it's the fullest. I think they empty the bins on Tues. mornings.