I recommend a dedicated server reseller, especially if you are new to offering dedicated servers. Build up a client base with a reputable dedicated server provider, and go from there. Most dedicated resellers get discounted pricing. Eventually, when you have the capital, you can purchase your own servers and colocate them somewhere. Remember though, if you own your own servers, you not only have to administer the hardware, but provide all sorts of spare CPUs, RAM, HDDs, etc in stock. Customer's don't like waiting for parts to be shipped
Hope this post serves you well!