What is the best open source platform to run online shop with plugins?

I would like to ask you for advice.
I thinks about selling audio plugins. But until I know if it would be profitable for me I don’t want to pay for platform like Shopify or something like that. That’s why I think about some open source platform.
I’ve heard PrestaShop has ability to sell downloadable products (like audio plugins).
But on that website it looks like the cost of such functionality is 199$ .

I wonder if any one of you can recommend any platform to start my online store with low costs and some nice, modern features. And easy to use. And with good stability, etc…