You may not see any growth for some time and then a gradual growth. A web-enabled company is a global company. People from al over the world will see your site. Don't be surprised if you get an order from South Africa. That may present some problems if you are not set up to do international business.
Smaller companies can start for very little.
This covers your name for two years. You will need to pay this amount every two years to keep the name. This covers setting the server up to host your site. This is a one time fee. This covers simple sites.