Hi Rudi
I would recommend getting memory products from from Transcend or Kingston. I have used RAM products from Transcend for over five years and have never had a problem. I recently purchased a 512MB Transcend CF card for my Canon and it was R400 cheaper than the Sandisk equivalent - there is most likely a similar price difference for memory sticks.
You can get Transcend products from specialist computer stores, or online at places such as:
ComXpert - Highly recommended,
Cyberdyne or
Digital Planet I have had good experiences with all three, but would especially recommend ComX. They are all, however, located in Gauteng, so you would have to pay postage.
Hope this helps
Cheers
Ed