For someone getting started out in a "normal" photographic workflow, Elements is good to get you going.
For shooting Raw, you might consider also installing the Raw processing software that came with your camera, Digital Photo Professional (DPP) and having the latest updates from the Canon site. It give quite good conversions and when you need the capabilities of a program like Elements you can convert to a tiff in DPP and open it in Photoshop.
As you've seen, the "full bore" version of Photoshop is expensive -- it has more tools and is geared towards a "high-power" workflow that enables a lot of automation and such. For most people, it can have too many features and be overkill, so Elements is a good place to start as you learn your way.