Has anyone ever tried using P&T Assets as a field with Carthrob? More specifically, I'm looking to sell photos that are located on my Amazon S3 account. Do you think this will work?
I think you should be able to do this using the {exp:cartthrob:is_purchased_item}
tag.
https://cartthrob.com/docs/tags_detail/is_purchased_item/index.html
You could just check whether or not the logged in member has purchased the product, and conditionally display the assets.