Ubercart

Probably the easiest and most straightforward way would be using the Cart Links module to create the link, and then style it so it looks like a button.

Settings info: http://www.ubercart.org/docs/1434/cart_links_settings
How to make them: http://www.ubercart.org/node/1427

Here's an article someone else in your same scenario posted, for Event Registration (and they talk about using Cart Links as well): http://drupaleasy.com/blogs/ultimike/2009/03/event-registration-ubercart

Thanks! this was helpful - I have created a cart link using /cart/add/p10 (where 10 is the nodeid of my event product node).

However, when I click on this link, I get the message that the event registration product was added to the cart, without being able to fill in the "event registration" node edit form. Ideally I would like the cart link to work in the same way as when I click the "add to cart" button in my event product node - drupal opens to event registration node edit form for me to enter my contact information and select a few optional product attributes.

Is there any way to create a cart link that opens the node edit form (I am using the UC node checkout module for event registration)?

Thank you