Did you know that you can donate old running shoes to groups that will give them to the less fortunate? Last year when I was running a lot, I bought 2 pairs within 6 months because of the miles that I was putting one them, which is definitely not a bad thing. And as I am increasing my mileage this year, I will go through more shoes, I'm sure.
I have probably 3 pairs that I don't use for running. One pair I use in the garden when doing heavy duty gardening and then one pair that I use for just regular everyday walking so my running shoes don't get worn out and then an extra pair somewhere. I could totally donate that pair to one of these places:
One World Running
If your shoes are really beat up, you can send them to Nike Reuse-a-Shoe program.
They use the whole shoe for different things like: