Have a look at this site - [url removed, login to view]
You can see on the product listing there is a "Already X sold!" notification.
My client runs a similar site, powered by wordpress + with payment via Paypal.
He would like to have this:
A script will be created which will communicate with Paypal upon successful payment. This script will add counter unit to the database.
An embed code will be provided so he can embed in a product posting. There will only be 1 product each time.
This code will display current units and once sold out will display sold out text.
You will also need to create a simple admin panel for admin to set quantity to sold out and also reset back to 0 sold for next product. So he can reuse the same embed code again and again.
This is the workflow:
1. admin enters simple admin panel with login / password.
2. admin sets product units to be "sold out" e.g. 50.
3. admin uses some embed code to be embedded into his wordpress post
4. when user buys, via paypal ipn (some URL to post unit sold to the dbase) will notify the backend that unit is sold, and code will display "1 sold!". If user buys 5 units, then it will be "5 sold!".
5. When 50 units sold, "Sold out" notice will be shown.
6. Admin can go back to backend, to reset new product unit numbers and set back to 0 sold.
7. For next product, he can reuse the same embed code in point 3, since it is listening to same dbase.
Site is on PHP / MySql.
Project needs to be completed within 1-2 days.