1) Forget about all these whacky forms of creatine. Get a 100% pure monohydrate.
2) For brands, I recommend brands that I have used that a) are very fine and mix well b) don't clump up easily c) have a noticeable effect. The best brands I have tried are Prolabs and Biotest.
As for where to get them, someone else could better answer that.
Read
this.