To determine your shared hosting needs, we typically look at three things:
1) How much disk space does your current site need? Upgrading or downgrading as needed should not be a problem. However, we recommend choosing a plan that will give your site plenty of space; if you run out of disk space, your site will cease to function properly.
2) How busy is my website? If you run a large and active E-commerce store, you'll want to ensure that you select an appropriate hosting package, as outlined on our hosting page. For example, a large E-commerce store should not be hosted on the Starter Plan.
3) Do you need a dedicated ip address? A dedicated IP address is needed for the installation of an ssl certificate. If you're processing credit cards directly on your site, you will want an ssl. If a dedicated ip address is needed, you'll need to go with at least the advanced plan as our smaller packages do not come with that feature. Otherwise, if you're using an offsite card processor such as paypal, then you would not need a dedicated ip and a smaller hosting plan should work for you if it offers enough disk space and bandwidth to support you.
Please contact our sales team if you have any questions. Otherwise, you may compare our shared hosting options and pricing here: http://www.mystic-technologys.com/plans.htm