My wife is a wedding and fashion photographer (as well as some family and maternity). We've been traditionally giving our High Res images as a part of the package price to our customers. Now that we've started using SmugMug for our client gallery, we're thinking about offering prints as well.
The problem here is that because we've been giving the digital copies for free, and because a client could take those digital copies to the cheap spot to get them printed... we're unsure where to "start" when it comes to print costs.
One thing we are considering doing is taking one of our images and getting it printed at SmugMug in "Gloss" "Luster" and "Metallic" and then also get it printed at Wal*Mart, Costco, London Drugs, Blacks, etc. This way we'll be able to show the client the difference in quality.
My question is, how can we go about pricing our images accurately and competitively? We want to be competitive, but we don't want to deter our clients from using a professional print lab over Wal*Mart.
Edit
Though all of the answers and comments thus far are very helpful, I feel the focus is on the fact that the digitals are free. I'm wondering a little more about how to price the prints.