Add Donations to Event Registration Form

Question

I'm trying to give people an option to add donations to special projects when they register for a particular event. We could just point folks to the contributions pages, but it would be more effective/convenient to just roll the donations into the event registration form.

Any advice on a strategy to accomplish this?

What I've tried so far:

• A developer friend suggested adding custom profile fields to the Register.tpl template and then saving the donation amounts to the custom fields using an ajax call. I've got that working.
• I'm not sure how to add my custom donation field values to the event amounts, which would be needed in order to actually charge people for their donations during the event confirmation and payment pages. (I've tried using the postProcess and buildForm hooks, but don't see how/where to change the "amounts" values.)

(CiviCRM 4.1.6; Drupal 6)

Answer 1

Simply set up an additional line item for a donation in a Price Set.

This is how I do it... the Price Set definition:

And then how the 'Optional Donation' is defined:

And a preview of this in action:

Feel free to give it a whirl on my website - and make a donation if you like it! :-) http://www.breinton.com/book/hipp-abbate

Answer 2

There is a similar but slightly different approach that allows the user to enter any amount for a donation. It is mentioned in the documentation for a membership price set, but equally would work for events:
https://docs.civicrm.org/user/en/latest/membership/membership-price-sets/#non-membership-price-fields

Add a Price field to your price set with these options:

• Field Label: Choose a suitable name and include the currency symbol e.g. 'Donation £'
• Input field Type: 'Text / Numeric Quantity'
• Price: 1
• Financial Type: 'Donation'
• Display Amount?: Uncheck this option

One caveat of this approach is that a user could enter a negative number in this field to dishonestly receive a discount!

Although there is an extension that was created to prevent exactly this situation: https://civicrm.org/extensions/negative-negator

I actually really like approach of Lionel Smith-Gordon's answer, and I might decide to use it myself for simplicity, however I wanted to add this alternative here so people were aware of this approach.