"I want to start a hosting company"
You want to start a hosting company and you are asking about VPS and Dedicated servers? Interesting.
I suggest hosting your own sites on shared hosting, VPS hosting and Dedicated Severs at several places for a few months before starting a hosting company. You'll be amazed at the unreliability and downtime you'll find out there. I've used shared hosting accounts and VPS accounts at several places and I've settled with liking GoDaddy Dedicated Servers (which have problems but the benefits outweigh the problems).
Pretty much all VPS and shared hosting accounts are too risky because you never know what the other people on the server are up to. They can add server load which makes your sites load super slow at times when you don't even realize it. This goes for big names like GoDaddy.com too (in my experience).
With a dedicated server, at least you know what your server load is, why it is what it is, and you know the rate at which you can scale your traffic without having problems. Since GoDaddy has round the clock phone support due to economies of scale, they are good enough (but you can't send more than 1,000 emails a day from the server on port 25 without getting special permission last time I checked - this stops spammers). I bet that most large companies which can afford true round the clock phone support are probably good enough for you to get a dedicated server at. I've used services that say they have phone support (really it means they have a phone number with an answering machine). Dedicated servers will cost you close to $100 a month (or maybe more). If your business isn't going to make you $100 a month, why do it? You might as well fork over a few hundred and get the job done right from the beginning.
If your resources are low, then become an affiliate for a web hosting company rather than starting your own.