Piecing one together and paying someone to build it makes little sense. The fact you have no idea what you are doing makes even less sense.
Do yourself a huge favor and buy one already built up.
Actually it makes a lot of sense coming from my point of view. First of all I get to pick out all my parts so I can get exactly what I want. Second of all I know how to build a bike I just don't got the tools to do so. Neither do my friends. Third of all my guess is it'd be cheaper to just have someone build it for me then do go buy the tools to do so myself.