How to create a small charity donation option in the checkout page?

Hi there!

As I am willing to support a local charity organization, I would like to create an option (an attractive logo/text manually activated by a checkbox or similar) on the checkout page to add a fix small amount of money to the basket, just before the customer proceeds with the payment. For example: Websites like Ryanair offers that option to support charity organizations during the payment process as well.
Maybe the charity donation amount might be configured as a standard product which needs to be added to the basket on the right moment. In that way I suppose I'll have to edit the template file of the checkout page.

Any idea how to set this up the easiest?

Thanks in advance!

Well, this Extension could possibly serve your needs, if you're on 1.5.x or lower v.2
Ernie
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Charity Donate
This extension adds a donate box together with a 'GiftAid' option to the shopping
basket under the "What would you like to do next?" heading. The donation amount
is added to the order total. The GiftAid option can be disabled in admin.
In addition
charity_admin adds the yearly total donations
charity_reports lists donations made in the admin reports section
https://www.opencart.com/index.php?rout ... on_id=5538
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