1) For having website you need to register a domain name (can be your dream name for your company)

2) then comes web hosting space where you will host your website.

3) Then find a Designer/Developer and get your website done from them.

4) Then comes Internet Marketing to start selling on your website.

5) Use Social Media to market, advertise and promote your business and increase your sales fast.

Well, you can consult a firm which provides all these solutions as Single window support. There is a firm in Pune, called Fameboss Creative. They are best at digital advertising, online marketing and social media marketing. I myself consult them only for my Vastu Consultation services. There are so many people out there in market, I spent so much on these marketing and social media thing on Big names. Finally found this Fameboss guys. They are cool. You must try them for your business promotion & marketing.