I’d like to ask about servers?

I am trying to start my first web app and I’m not sure about which non local host servers to use or what kind are best and what cost’s are associated? Then the next hundred steps from there after this part of it is ressolved in a perhaps more laymen terminology or with some basic tips and understanding on how to create an app like a pro would help also.
I’m intending use for such app on various websites with different variations of XML and any assistance on which site is easiest to use that will also accept a perhaps less advanced app than usual will be of great help to me.
cheers.