I would go for a VPS, because you can afford it with your budget, and also because it gives you a lot of knowledge that you do not have with reseller accounts. And when you get to dedicated, its 99% similar like a VPS.
Start with a reseller first. However, if you are technically ready, VPS will be a good one for you to further expand your skill. Then slowly progress to dedicated server when you feel confident enough to run the whole thing on your own. Of course, you can get managed service like PSM. However, as a webhost, it is better to know the minimum technical stuffs for your own good.
For a VPS you would most likely need some kind of managed service (or outsourced management), which might set you off your budget, unless you have the skills and resources to do this yourself. Because of this, it would be a wise desision to start off with a reseller account, keeping your budget in mind, and grow from there! Good luck
And would you tell me Books that can help me to grow my knowledge for supporting my clients. and a good reseller account to go with (to be able to upgrade to VPS and Dedicated)? is Powervps a good choice or you would recommend other one?