I want to build a simple PayPal express check-out system. On my page are two products I offer which should be able to directly be purchased (without registration). After paying the user should get an email with an individual generated code for a streaming content.
How do I realize that?
I had to do something similar recently and I found the best way was with a combination of PayPal's "upload cart" function, and PayPal's IPN callback. Relevant links;
Tool to generate a "Buy Now" button <- easily modified for a cart upload using the next link
Variables for cart upload form
PayPal IPN (Instant Payment Nofitication) documentation <- you can set the IPN URL as a variable on the upload cart form as well, PayPal will immediately call on this URL, passing relevant data, upon checkout completion
Using the above you can upload several items to a cart in one click, you can also include custom data that will get passed back to you via the IPN call. That should be enough to get you started.