simple facebook application

we need a simple facebook application as follows. * We will display a product in our facebook wall * When our app user clicks on the link, it should take to the application page, where they will select the quantity and click place order. * once placed order, a comment should be placed under the product on our wall says " user placed this order" , this should be done on behalf of the user. That's it. pls. post only if you could do in 30$ budget.