Alps yes they do cost a bit however on a track day you will just ride your bike as you always have done and maybe not know why you do certain things.
On the CSS course they will teach you how and why things happen, what you can do to make things better for you and maybe teach you new things aswell. Everyone starts a the same level no matter what your experince is as the coures build on each other so you get a full inderstanding of what they teach.
i have been rideing bikes for over 10 years and they certainly taught me new and usfull things, I would reccomend them very highly indeed.