You won't know if you're getting a real bargain unless you really know what you're buying. For instance, if you're getting a PDA bargain because the unit was made last year, what features are you sacrificing for a few dollars? Perhaps you should think about getting a model from this year that is refurbished or out of the box.
Being informed about the technology you plan to buy should be incredibly important to your decision making process. Go to sites like epinions.com to get inside information and go to the manufacturer's websites to learn about the features and functionality coming out soon.