Be extremely cautious while communicating with the owner. Even if you casually agree to buy the domain via email, the communication might be used against you in court as a legally-binding contract should you change your mind. Until you’re absolutely certain that you want to make a deal, agree to buy the domain provided that all the terms are agreeable. This will leave you an escape hatch if things go south.
That said, not all web hosts offer email. WP Engine, for example, does not. In such instances, you must email accounts from a company other than your web host. GoDaddy, for instance, sells email packages starting at $3.49 per user, per month. That might sound like a hassle, and just one more thing to keep track of, but there are actually some webmasters who feel that separating your email hosting and web hosting services is smart. That way, one provider going offline won't completely bork your business.
Do you plan to sell products or services? If so, you'll want to invest in a web hosting service that offers Secure Sockets Layer (SSL). An SSL connection encrypts the financial information that shuttles between users' web browsers and your website, thus safeguarding the transmission of the purchasing information. Some hosting companies include a free SSL certificate when you sign up for a web hosting plan, while others charge close to $100. You can save some money by shopping around for services that offer the cheaper SSL plans.