Well, Laurent charged only $ 500 USD for his solution (but that's an anomaly).
If you are serious about web apps, then scaling the back end comes into play, which means getting into distributed systems. Networking, security and SysAdmin become relevant as well.
I think it's fair to charge up to $100K with a college education and/or work experience in the field. Other professions do so as well.
Go pick on other professions: i.e. banker bonuses, real estate commissions, union rates, lawyer rates etc.
so you are saying $500/hour is industry average? Hackeronymous mentioned that he charged $100k for a 1000 hour work which he could have done in almost 1/6th time if he was experienced. I am not sure about the industry average, but I work through guru/elance/odesk and average seems to be $50-$150 for an experienced developer.
No, in the example on this thread Laurent, a Belgian programmer, charged $ 500 USD for the whole solution, the whole shebang. (He could have just given it away for free, since the main point was to establish a reference)
Although, I admit... this example is really just a CRUD app, with no advanced server back end.
If you are serious about web apps, then scaling the back end comes into play, which means getting into distributed systems. Networking, security and SysAdmin become relevant as well.
I think it's fair to charge up to $100K with a college education and/or work experience in the field. Other professions do so as well.
Go pick on other professions: i.e. banker bonuses, real estate commissions, union rates, lawyer rates etc.