I try to support my LBS when financially sound. Something's I just can't afford to purchase there but majority of smaller items and wear parts they are close enough to online so I support the best I can.
I rarely use the repair side of my LBS, only if I can't fix it or don't have a specific tool that isn't practical for me to purchase. Usually when I visit my LBS I get a cookie and a cup of coffee at the same time and a friendly chat if I buy something or not. They are excellent at CS, but then again I do buy all my bikes at the same store.
Anyways $20 isn't unreasonable to me. I think that is fair, a shop employee gets paid a wage and all the expenses of owning a business are pretty steep so I think that is fair.
What happens when all the LBS do close and only the "box" stores are left? Then I think things would really get wonky.