he probably factored in all the time he spent learning to build the first app, and then multiplied it by 10...if he's an independent developer i'd be very hesitant to contract him given his poor billing techniques
On the other hand I would be quite hesitant to hire a developer to build a customized video player for tens of thousands of dollars if he was going to go on and sell that same code to others for $200 a pop.
Neither approach is right. There's nothing wrong with the write-once sell-many approach, that's basically all of non-custom software development. You shouldn't be charging for your time to learn, either. His 10 apps aren't worth $500,000 in any universe. Maybe you could argue that the entirety of the development was worth $50,000 and value each app at $5000. Maybe. I wouldn't argue that, but someone else could...
