0% down!!!
I am willing to work for relatively cheap on this project. I am currently out of university for one month and am looking to expand my portfolio. I have ample time to spend on your project, as I do not have a day job. I just created my account today, and have not yet been able to post anything on my portfolio. I have little experience, but I have completed projects to specification and am willing to work for far below market price so as to be able to build experience. I am also willing to take 0% down, and will sign a contract with you detailing a specific time frame, method of payment, etc.
I plan on using javascript functions to calculate the price. For instance, i have x phone. I enter x phone into a text field, which dynamically searches and returns used market value with phone condition factored in (in percentile, >25%, >50%, etc) for the phone. I would then use market data to return a rough estimate of demand (for purposes of resale) for said phone. Using your specifications on preferred estimated resale time, I would take the average realtime value at somewhere around the 10th percentile (the low 10%), add in your preferences, and there is the price.
I have taken multiple college-level statistics classes and have shadowed at an A/B Testing Firm and have a general idea of the way to use market data in code.
I will use HTML, Javascript, CSS, and jQuery.
I sincerely hope you will contact me for further questions and clarification.