Good Link Dereck. There is an additional reason not mentioned in the article. Developement/Design cost. This cost adds an addtitional layer to the price and manuf try to recoup this cost in the first couple of years. The Case of the M4 vs the Samsung 830, the M4 has been out longer so a greater percentage, if not all, Developement/Design have been recouped, hense they can drop price sooner than the 830.
Another possibility is that curcial could be getting ready to come out with a Newer version and are tring to reduce stock as when the "newer" version hits the market the demand for the older version drops - JUST a Quess.
My Take, there is not a significat difference between the M4 and the 830 to warrent mort than say a 10->15% price differnce.
I have 3 M4s (2 128 Gigs and one 256 gig). The 256 gig That I just bought last week was cheaper than my first 128 gig M4. Also hve 2 128 gig Samsungs.