BigCommerce is a bit different from our other hosting plans in that it's a SaaS (software-as-a-service) provider instead of an IaaS (infrastructure-as-a-service) provider. In other words, rather than renting space on a virtual machine where you setup and configure your own site, BigCommerce provides you with an app you login to that creates and online store.
Almost all the services offer some sort of drag-and-drop website builder that makes it easy to drag and drop items to build your page. These are great for getting started, but they often lock you into the service. Most page builders are proprietary to the service, or don't create HTML that's portable enough to be easily moved to another service if you decide it's necessary.
In housing terms, VPS hosting is like renting your own apartment in a larger building. You're much more isolated than in the roommate situation mentioned above; it's still possible that a neighboring apartment could causes annoyance for you, but far less likely. In web hosting terms, Site A's traffic surge won't have nearly as much impact on Site B or Site C. As you'd expect, VPS hosting costs more than shared hosting. You'll pay roughly $20 to $60 per month.