How to override collectTotals function In Magento?

Question

I want to add a custom value, i.e custom fees, in the cart page below subtotal, so the Grand total should contain the custom fee. Here i mean to say that during quote-state, the grand total should contain the custom fee. And from the quote- to order-state, the grand total must contain that custom fee.

Answer 1

What you need to do is add a custom "total" entry that will be added to the grand total.

This guide will get you started.

http://turnkeye.com/blog/magento-development-add-total-row-checkout/