Need to get in contact with a really good app writer! Android primary and apple secondary.
You need to be perfect with your job about this app!
The app could be a big job and it need to be updated once a month. Make the app easy for other than you to input new data.
You must be good in photoshop so the app looks realy nice!
The app is about sharing and trading, so you need to know and make solutions for this. In example: Have a file, touch the selected file and swap it with another android unit.
We will arrange an agreement on a fixed price of the app. Give me examples on projects you done, and the price on those projects.
Get in contact for more information