Ecommerce plugin, simple

Hi there
I don’t want to make a webshop site, I only want to sell a single digital product (ebook) from my site. I was told that there exist very simple solutions out there, but after endless searches day and night, I must admit that I got lost in services and plugins.
My programming skills are limited to HTML, and I am looking for something (almost) free. Offering the buyer a VISA payment option and a unique download link. I will be happy to hear about your experience doing similar things.
Thanx.
Jesper