I bought an 8Gb 'Genuine Sandisk' card on ebay. It did not work and even though I have started a PayPal dispute, I cannot make the vendor understand tat I want a refund. "No spreek Engrish!"
i think by far the best place to get MINISDHC or any memory cards in general is everlabs.com, its a quick register (no money needed) and you get access to all the products. I bought my 4GB SDHC card for 23$ shipping included. It's 5-7 days airshipping and the caards are brand new, i would really advise you to check it out.