I got both of my adata 8gb from newegg($6 shipped each) and 16gb($21 shipped) from them as well, ebay is way more expensive and they usually charge shipping on top of sale price. They have deals regularly but not on at all times though. Make sure they are class 6(or above) since class 2/4(class 2 -2mb - class 6 - 6mb and so on) are way too slow(if class is not mentioned its the cheapest class 2) . If you not in hurry keep checking:
www.fatwallet.com and
www.slickdeals.net and
www.spoofee.com - forums of deal seekrs that will tell you when good deals come up(microsdhc or anything else for that matter
(like my brand new 40gb ps3 for $129 shipped from year ago
)). i myself waiting for 32gbto come out since i have a feeling touch pro/diamond will support it as well