I am new to this sound system stuff, all I ask is that if I buy my components piece by piece, will I be able to run say one center channel speaker and a sub alone with a 5.1 receiver or do I need at least 2.1 before I can begin? Thanks in advance.
No you can hook it up one at a time. Just make sure in the receiver settings that you turn all non-existant channels off. This will route all the sound through the speakers you have connected.
The speakers you should buy in order are the fronts (left & right), the sub, the surrounds, and then the centre channel. Whether to buy the surrounds or centre first is debateable, but that would be my preference.
A common mistake when putting only front speakers into a 5.1 set-up is to not set the centre channel to "None". This will make voices in movies either too quiet or completely silent depending on the track. Setting the centre to none will route all voices through the front speakers.
Buying one at a time can be vastly more expensive if you are buying from a retailer. Buying on-line is preferable if getting components one at a time.