After testing different e-Commerce Extensions i decided for j2store, because it works simple and i can customize it without a deep knowledge of php and css. This extension can turn content into a product just by adding the 'Add-to-card' box. My shop sells plants and herbs and so i can add the 'Add-to-cart' box to every plant-description i want to. I am a local nursery and i dont have to worry about international taxes or different shipping costs.
The forum is managed by the developpers and i got all problems solved and all questions answered. I like it.