SSL, or Secure Socket Layer, is "an established industry standard that encrypts the channel between a Web browser and Web server to ensure the privacy and reliability of data". It's more commonly known as "the little lock icon that appears in the corner of the browser."
If you are planning on transferring any sensitive data -- for example, if you want to sell products on your website and the user must enter their personal and payment information, or if you have users login with usernames and passwords -- then SSL is a must.
If you choose secure hosting then we will completely handle the acquisition and maintenance of your required SSL certificate. This includes any costs that we incur.