Depends on if you buy everything on the prof's list or just what is needed. I buy the required text that first assignments are drawn from, then go to class to find out what books the rof will actually use. Typically, a prof will list 5 or 6 books on his list, but only use 1 sometimes 2 in class.
If you buy everything, you'll spend around 700-800 dollars. If you buy only what is really needed, you can get away with spending 300-400.