Dear Sir,
We have developed similar kind of site previously. The site contains online shopping cart, product display and searching facility of product by category and name. Apart from that we use paypal as the payment gateway for the site. We use third party paypal code for connectivity. Apart from that we work on medical domain. We have products on Bloodbank management, Oncology management, Patient management, Fertility management.
We can give you the best cheepest solution for your project.
Regards,
Rikson