I agree with Rochen 100%.
As a "newbie", you must be careful not to go down the "disk space and bandwidth" path and think this is all your clients care about.
If it is.. then you are probably not going to succeed unless you have a LOT of clients or a lot of capital.
It is much better to focus on how much it costs to pay for your high quality support and service, your reliable servers, and your operating costs...
Once you have your costs nailed down, add how much profit you want to make.. and THEN you can calculate your necessary pricing for your packages. The amount of disk space/bandwidth you offer is 100% dependant on what kind of customer you are trying to attract.
If you are trying to attract local hosting clients, like designers and people looking for *quality*, then they won't care what you offer as long as it is on a 100% reliable server with instant support.
If you are trying to attract "quantity" customers, then 5gb disk and 50gb bandwidth is enough for perhaps a single $10 account. There are still 1000 companies who offer this even cheaper.
I hope that helps.