Oscommerce

osCommerce is an open-source eCommerce platform providing both a storefront (customer facing) and administrative backend. Key features:

• Free core platform: no platform fees for payment processing.
• Built on PHP & MySQL, extensible with many apps/modules.
• Supports SEO-friendly URLs, mobile-friendly front ends, GDPR compliance.
• Integrations available with major payment gateways (PayPal, Stripe, etc.) via modules.