Magento 2 is a PHP based Open Source e-commerce system and one of the most popular cart softwares.
We build B2B and B2C stores based on Magento 2. Depending on the requirements, the free Open Source edition can be used. The B2B modules and some other Enterprise functionality requires the Commerce edition with a yearly license fee.
Magento 2 is a complex but powerful platform. We recommend it for medium to large businesses.