I'd like to play around a bit with an online shop. Nothing professional with proper requirements, just a hobby project. When googling for open source e-Commerce solutions, I can find the usual software. But I don't like open core models, and all the projects seem to want to make some money with an add-on marketplace. And most of the times the basic product seems very limited and they want you to extend it with proprietary extensions to get it usable in real-world scenarios.

Is there a project that does things differently? I mean for invoices I can choose between several platforms that won't push me to buy anything. I just can't find an online shop solution like that. My requirements would be something along: Sells products and keeps track of remaining stock, maybe sells services like online courses and software/pdf downloads. Can generate invoices and ties into payment providers. Maybe generates shipping labels. Isn't too bloated, a small, nice and clean hobby project will do. I'd like to avoid running a Wordpress/Drupal/Joomla underneath it if possible.

I get that companies have different requirements and commercial products are somewhat the obvious thing if you're doing commerce. But there has to be something aligned with the virtues of the free software community. Something I'd like to use to sell Tux stickers and power my Etsy shop with.