Any good alternatives to BrickLink?
BrickLink is by far the best place to buy LEGO. It is also very easy to use. Once you get how it works, you will never look back. There are several very helpful videos on YouTube showing you how to use BrickLink most efficiently. Here is one: http://youtu.be/Cyat8aFVk_k

I have also put together a detailed written guide on how to use BrickLink here: http://thebrickblogger.com/2011/02/shopping-on-bricklink/