Write an Android application

Hello, I'm looking to get a quote / overall cost for a simple, smooth, elegant wallpaper application / template that is easily edited for future uses of other images. The artwork to be displayed is my own work that I've done over the last six-10 years. I would like several features that would make the app easy to use, fitting of all mobile types (including Tabs and such). Graphic design is important, but I'd also like it to be something I can edit. Flat style preferably. Features I would like for people. Categories to choose from, with two or three categories that are locked. Available for purchase. Favorites Option to Set as Wallpaper, download or simply few the image. Option to have them choose several wallpapers for rotating images - fade in fade out. (if possible). Option to have them share A option for them to purchase, ad free, with additional wallpapers to add. (see Above, locked categories). No need to crop - add the images to fit automatically, depending on what Mobile device is being used. Also, lite - if possible on battery load. I'm entirely new to coding and such. An admin panel on the backend for me, would be wonderful, but if that adds to the cost significantly, I will leave the option out. I want the app to be streamlined, simple and effective. But beautiful, which is important to me. I would also like it to be ready to be sent to Google and others, with information on how to prepare the app for that process. (First time app for me!). Ad ready for both Google and OS if possible. Anything else you can suggest for the app would be wonderful too, so I can add other ideas I haven't thought of. If you already have templates for previous clients, would love to see what you have done, to get an idea. Not a huge budget, but I would like to continue working with the same designer on other possible projects as well. Future work is likely. Thank you :) Look forward to hearing from you soon!