Hi James,
Adding custom fields to the event details can be done in the event category page(http://take.ms/e6FhH). You could create new fields like textbox field that the event creator can use to enter anything including event cost.
As for online payment, I do not think there is such a field currently that integrates with an online payment system, and there are no 3rd party developers that are doing this currently.

Ideally it would be nice to have a Paid Events Application that would support the above features as well as a few other small features and a hand full of the most common payment gateways.

Yes it would be nice to have some kind of integration with a payment extension. Perhaps you can start a thread in the feature request category so we can have other user's input on this.

Sorry, Raymond I think I misrepresent what I wanted to achieve.

I need to know how to edit the template files to add the contents of those custom fields into the header area of the events. See the attached image to have a better understanding. Thank you though for your explanation.

Thank you,
James

Hey James,
Alright I understand now. Unfortunately, there is no simple way to achieve this currently.

Having said that, if you require us to customize this for you, you can always request for a quote from us at https://crm.stackideas.com and select "Customizations" . Our sales person would be glad to send you a quote for the customizations that you have requested.