Android app

I need an Android App with following features: **Back end for Admin : He should be able to post his requirements ( things like laptop, mobile furniture etc ) which he wants to buy for himself. he should be able to click a photo, add his description and should be able to put his add on the app. Only the registered users should be able to see that add. **Front End for user : The person should be able to see adds ony through login. Once the person puts his login credentials in the app, he should be able to put his price for one item, ( means he will put the price he is offering to sell that product to the Admin) Like this all the users will post there price for a particular item.. Admin will get all the entries at his end, and he will decide MANUALLY that from whom he has to purchase that item. The payment will also happen MANUALLY, we don't need payment gateway on APP.