This seems a good price for an official Wii memory card. 50% off RRP, and cheaper than anywhere else I have seen it.
The SanDisk SD Gaming Memory Card line is the must have card for the Nintendo® Wii game console. For maximum performance and to get the most out of all the advanced features on the Wii, you'll need a SanDisk Gaming Card. With SanDisk, you will be able to download and store games, store game saves, and edit and store photos.