Wow... the lack of business skills is thick in here. Don't ask them to "put a number on it", they can't be both buyer and seller... What is your time worth?

Wow... the lack of business skills is thick in here. Don't ask them to "put a number on it", they can't be both buyer and seller... What is your time worth? $100 bucks an hour? $200 an hour? How much would cost you to recreate it? Are they asking you for a non-compete? Do they want exclusive ownership? or just asking for a license and you own the rights? If this took you 4 weeks @ 30 hours a week and this is your first project... it would probably take someone who knew android 1 week (40 hours) @ $125 per/hr so $5K? Ask some questions... develop a friendship with your customer... find out what they are doing and what they need it for and how they'll use it... use that to set a price. This is a stepping stone... be greedy and it will get around... be a chump and that will get around too... If you think its worth $10k ask for it and be flexible when a counter offer comes in... you don't exactly have other offers floating around.