Most of the lower prices that you're going to find are going to be from eBay, which isn't that bad of a place to shop online now-a-days with the whole buyer protection thing. The Toshiba Satellite series is very good (mine's an L675 and I have experienced no problems when doing the things you want to do). A good way to shop based on price, that I've found, is Google Shopping.
Here, for example. The only downside to that is you need to know what you're looking for. As for an actual recommendation, I would say definitely go with the Toshiba Satellite C655 (
here it is on the Toshiba site if you want to see the specs).