Alkhem and Helios Platinum and Gold is the place to start. Any of those. All if possible. And then after that in succession Lumin, Innerphaz, Phasix, 7 rays and any of the Helios line alchemies after HElios Platinum and Gold. Seriously consider a Puramyd though in addition to Alkhem and Platinum and Gold. They are all pretty affordable and you can just get what makes sense for your budget either getting them all or one at a time.
I have linked below so you can read about the first two.
I know it is a bit overwhelming. But we ALL started at the beginning and that is the way to go. No need to buy a huge amount of alchemy unless you are overseas and trying to save on shipping.
If you have any specific questions then let us know.
:) Hope that helps clarify!
The better site to use is http://blueemeraldalchemy.com