Why are screen fixes so expensive?

I dropped my roommates 3G iPhone the other day and had to pay to get it replaced. I went on the internet to see what my options were and found that Apple charges $199 to replace the screen and digitizer. I was looking around on the internet and found out that you can buy all of that from amazon for $14.44 and it takes about an hour to fix it. I also found a lot of 3rd party companies that can do it for between $30 something and $99. Long story short, I ended up paying the $210.77 after tax to get it fixed at the Apple store. My question is: why is it so expensive to get the screen fixed? I mean, it took the guy less than 10 minutes to put a new screen in, so the labor couldn't be that bad, and the parts cost around $14.44, probably less coming strait from Apple. I mean I already bought the phone from Apple, it seems they would want to keep my business by at least fixing the phone for a reasonable price like maybe $50 or so. I own a lot of Apple products and this is the first major complaint I have had, but I don't know who to contact to get a real answer about the price of the screen. Can anyone help me out?