1. u can set ut own online stone, u need to sign up with vendor who's all doing selling
2. payment gateway u can choose third part or bank
3. shipping cost based on order cost or make it free u option
4. return based on ur website user and traffic
we are UK Base Company , Development center in India
We have dedicated team for PHP, Mobile Apps ( iOS, iPad, Android), Organic SEO and SMM and digital Marketing, and we have developed and deployed multiple scalable applications on various PHP frameworks/tools like CakePHP, PHPClassifieds, Laravel, Angular js, node js, Joomla, Drupal, OXID eShop, Magento, Wordpress etc.