Ok I see it like this from what I heard, if I get a reseller account at a place and like I get a 2GB account then if I sell the space like a package for 500MB and whateva bandwidth per account and 2 people buy that account would I have only 1 GB then and if this is true, how do I upgrade if I need more space etc.

it really depends if the host you choose allows overselling on reseller accounts.
if they do then it means you can sell as many 500mb accounts as you like, until that space is physically used up.

as for upgrading your account, this should be available for all hosting companies. and normally requires an email to your host asking for your account to be upgraded.

yes but what I mean is if I have a 5 GB account for reseller and I give out a 5 GB package and someone buys it does that mean I have no more space and need more?

ok if i had a 5gb reseller account, and a host allowed overselling, then i could sell 20 (number off top of my head, not recommended though) of those 5gb hosting accounts.
say on average out of the 20 hosting accounts you resell they only use 100mb of their 5gig. That means a total of 2gig is being used of your reseller account. Leaving you with 3GB to do what you want with, i.e sell more 5gig accounts ;)

now if a reseller does not allow overselling then you would only be allowed to sell the one 5gb package.

Is overselling like if u had 5 GB space reseller account and they had overselling that u could sell as many accounts as u want for 5 GB packages but u wouldnt have to use up the space that u get from u reseller package and that the company would just give out the space for u...lol kinda confused

hehe, i think your missing the point.

ok imagine this, an airline company oversells. It allocates a certain number of seats for a plane, but they always sell more tickets than there are seats because some people are bound to not turn up.

now imagine that in terms of web hosting. the number of seats allocated are the same as your limit for disk space and bandwidth. but you can allocate more than your limit because people never use everything that they are given.

so if you get a reseller account for say 2gb and started selling 100mb accounts. a hosting company who did not allow overselling would only allow you to sell 20 of these accounts because that would take you up to 2GB. they do not allow you to go over you allocation.

now if you had a hosting company who did allow overselling, it means you could sell as many of those 100MB accounts until the space is physically used up. Meaning the total size of all the webpages, images etc of your customers reaches the 2GB limit.

I get what ur sayin thank you for shedding some light on this subject for me