A complex site calls for a more comprehensive package that provides database support and application development platforms (e.g. ASP.NET, ColdFusion, Java EE, Perl/Plack, PHP or Ruby on Rails). These facilities allow customers to write or install scripts for applications like forums and content management. Also, Secure Sockets Layer (SSL) is typically used for websites that wish to keep the data transmitted more secure.
Many web hosts offer limited features in their starter packages and then expand the offerings (sometimes tremendously) for higher-tier plans. Read the small print to make sure the plan you are selecting offers what you need. If you need a site builder application to design your website, make sure that the low-cost web host you are picking actually comes with a site builder. Many of them require you to pay for the builder as a separate add-on. Website builders usually don't cost a lot of money, but if you can find a web host that includes one for free, that's money in your pocket. And, if it's integrated with your hosting service, you're more likely to have a smooth, supported experience.
^ March 16, 1992 memo from Mariam Leder, NSF Assistant General Counsel to Steven Wolff, Division Director, NSF DNCRI (included at page 128 of Management of NSFNET, a transcript of the March 12, 1992 hearing before the Subcommittee on Science of the Committee on Science, Space, and Technology, U.S. House of Representatives, One Hundred Second Congress, Second Session, Hon. Rick Boucher, subcommittee chairman, presiding)