Knit Happens....this is a great store in a great location with extremely helpful staff. They do offer a variety of classes and there is a great selection. Also, the samples they have provided really do inspire you if you're in a knitting bind.
But, this isn't the best place in the Phoenix if you are new to the world of knitting. ONLY for cost reasons. Sure, if you have a boatload of money and want to drop it on some great yarns - then by all means, have at it. However, there are plenty of other local knitting stores that offer less "pricey" yarns that are just as nice for first-time projects. (And I 'm not talking about Michael's or Hobby Lobby...)
That being said -- this is definitely THE place to get your finer fibers. And when I mean finer, I'm talking $$$$$ finer. Beautiful cashmere's (NOT BLENDED), wonderful alpacas, soft soft soft silks.... I completed a pair of socks using cashmere and the total came to about $60 for my supplies. A typical blend that I use often would run me approximately $20.