First, if you need to buy something in Cambodia, you should be able to find it.
However, with regards to the above post, keep in mind that Cambodia isn't exactly a bustling economy -- many billboards that are up, have probably been up for a long, long time. Just because there's an ad for the D200 doesn't mean that it's the latest model there.
I say this after just returning from Cambodia -- while I wasn't fishing for gear, I did peruse for memory cards a bit (VERY light perusing) and I didn't see any great deals. At least no great deals on real, and not imitation, products.