Well this is something I've been thinking of lately, not to buy, but to sell. Since my network of websites are growing, so are my hosting limits.
I might buy a reseller package from Hostgator, and sell the bandwidth & space I'm not using to some friends I know (but not to the hole world). With that money, I could earn some money back off the hosting package and eventually when it gets bigger I might buy a VPS, after that dedicated server and than I might start a little hosting company.
But that will only be done in a few years, not in the first 3 months :rofl::p
Investing $200/month on a server when your just starting would be stupidity. Not all resellers are bad. But if a company offers you hosting below $20/year (They still make less profits!) will remain on the reseller forever. A company does needs funds to go ahead from a reseller to a dedicated server/Vps. :)