Most everyone has heard about the depletion of available IPv4 addresses and the urgency to get new IPv6 ones. IP addresses have a limits,so to compensate for that web hosting providers offer shared hosting accounts rather than dedicated IP hosting.
Whether you are using web applications for CRM (customer relationship management), POS (point of sale), or for an e-commerce storefront and shopping cart, you will probably want to make sure transactions, logins, and the collection of user data is secure. Unless you are using a third-party e-commerce provider to handle transactions, the best way to make sure they are secure is to use SSL (Secure Sockets Layer) or TLS (Transport Layer Security). With this security technology, your customers will connect to your site via secure HTTPS rather than plain HTTP.
In order to function properly, SSL requires a dedicated IP address, and many web hosts will offer special packages for e-commerce users who need them. You will also need an SSL certificate, which user agents (web browsers) will use to validate the authenticity of your secure transaction. Anytime a customer initiates a transaction on your secure site, the information exchange will be encrypted and safe from prying eyes.
So can you have an e-commerce site without a dedicated IP address? Yes, but not having SSL certificate will prevent you from being able to offer customers a secure shopping environment directly on your site. When it comes to customers you want to build a trusting relationship, and for that, you will probably need a dedicated IP so as to be able to offer them the security they need.