I have used custom options to create a drop down for prices based on weight of products(like, 250gms - $10, 500gms - $20). I am looking to add it in product listing page. I have gone through this solution given by Vinai in stackexchange.
http://magento.stackexchange.com/a/4499/27113
But being a beginner in Magento and PHP, I was not able to clearly understand what are the changes needed in
- catalog/product/view.phtml
- product.js script
- catalog/product/view/options.phtml
It would be really helpful if someone can give little more detail about what the changes are.