Creating a APP to load and unload files from the phone to ftp folders

I want to create an application for iPhone and Android that works as does a standard FTP client. The application should take any kind of files from any folder on client phone and upload it to a root folder associated previously with the device, then the person could check folders in the APP and files and can download them again to the phone . This type of application and there are many in the market to Apple and Android and can be found in the search engines under the name "FTP client" in this case my application should be similar to any of these but personalized. We do not have a big budget , so we are a couple beginner preneurs so please do not respond if your budget exceeds the stated range Please send a fixed budget for the total work. Thanks for taking the time to read my ad