What do i need to purchase to start except the re-seller
A good reseller package and a domain name.
You will also need a lot of time, but dont expect to make enough money to live off for some time. If you have a full time job, which you will probably need to finance your hosting project then who will do the support when you are working? There are a lot of things to think of. If you are not around to answer support tickets then your customers will get grumpy.
How do you plan on getting customers? We got many of our first customers from other projects so if you are starting with none then things may run slower.
Roughly how much would i earn once i had got some customers and was an average size?Would it be enought to live off?
IF you do it right then yes you should make enough to live off. How long from now this may be? Dont know.
We have been hosting for over 3 years now. The first year we would not have been able to live off, if we were not working on other projects at the same time. Now hosting is one of our main businesses, we own all the servers in our network and are planning a move into our new offices.