This is a nice friendly place.
I have sent off several paperbacks and even one hardcover which I knew was good,(I own a copy) and when I saw a cheap remaindered copy I bought and freed it!
At our library there is a rack of used paperbacks priced at 25 cents each and if I see a good one I will spend the quarter and free the poor neglected thing.
There are folks who read Book Crossing lists regularly and go "hunting" books that are in the wild.
And don't limit yourself to adult books ... children's books are great to free at your local shelter.
Do give it a look. It's *FUN*.

The fact that it makes you feel good is just a bonus.