Adding other sub product inside product

Not sure how to do this bu,t it is my next project. I have two products on my site. I need to add a text field to the products that would allow a customer to donate how much money they would like to be added to the product price. The product would have a field labeled Newcomer Donation and if they entered 10 in the textbox then $10 would be added to the $40 product price and in the cart it should also show as $40 for product and $10 for newcomer donation. Thanks for any suggestions at all.

Posted: Oct 7, 2012