How to charge customer just 20% of the cart total at the gateway.

As the title suggests, how can I charge just just 20% of the cart total at the gateway?

eg: If the cart total is $100, when the user click on buy now using a gateway such as paypal, the fee to pay in paypal is only $20 (ie: 20%).

Thanks

If you need the fee IN ADDITION to the cart total, then Simple Payment Fee can do that. If you want the TOTAL AMOUNT to be the percentage that you want (i.e. the customer only pays 20% of the actual total) then you can still do it with that extension, you just need to set it up as a discount. For example, you'd use an 80% discount to get the customer to pay just 20% of the actual total.

Feel free to take a look at the screenshots and demo site, and if you're interested let me know at www.getclearthinking.com/contact if you have any further questions.