Newegg is also a good place to get memory cards and stuff like that for cheap, or tigerdirect.
As OutsideTheLines said, if you have a DSLR you would then want a faster memory card. But a point and shoot you really don't need anything crazy. The price of memory cards went down so much that it really doesn't matter anyway. If it's a point and shoot a 4gb card on a 6 or 7 megapixel camera would store easily 1,000 pictures. So it's almost unnecessary to get a huge memory card except that they're so cheap now it doesn't matter.