Hello Tobias,
My name Is Hamza, I'm a web developer/designer, and I believe I have the necessary skills required to help you with your website. Can I ask please how many pages needs to be connected together, and also more details about the connection it self. As for the small example you mentioned, doing that is really straightforward task. I also would love if you can clear out the connection of the user's purchases part. Looking forward to work with you, and feel free to contact me if you have any questions.
thanks