Check with your school's bookstore. They can probably offer you some discounts. That's how I got mine.
The only laptops you should be considering are ibms. IBM recently released their new models for the year, so you can expect the new system prices to fall in the coming months. IBM doesn't discount their comps in waves though, it happens randomly over time.
I don't know why people on this board have such a hard-on for IBM's. They are incredibly expensive for what you get. Sure they are rated highly but there are a million brands that make great computers. Just research what you want and get it. Check out www.cnet.com. As far as the best timing goes to buy a computer; I've often wondered that myself. To say that the time of the year has nothing to do with deals is completely foolish. Think about it. A lot of people are buying computers now in preparation of the impending school year; therefore companies are going to be more competitive in their pricing.The same thing goes for times around the holiday season.Their is nothing random about pricing.