The trusted Photography store Adorama has some great deals on SanDisk memory cards. It’s not the golden instant rebate, but if you’re willing to deal with either a gift certificate towards a future Adorama purchase or a Visa Gift Card you can get some cards for about 50% off. The rebate details (PDF link) show that they apply to both Extreme III and Extreme IV models – including the ridiculously fast Ducati edition cards which boast up to 45MB/second sequential read and write speeds – but the speed differences between the Extreme III and Extreme IV cards are probably not enough to make people want to pay as much for a 4GB Extreme IV card as they would for an 8GB Extreme III card.

If your camera takes compact flash, I would tell you to choose the 4GB for $38, the 8GB for $60 with free shipping, or the 16GB Extreme III card for only $105 with free shipping. If you’re not shooting with a higher-end SLR or you happen to be rockin’ a Nikon D40, you should look into the 4GB or 8GB Extreme III SDHC (Secure Digital High Capacity) cards for $20 and $38, respectively. You can save even more if you buy more than one card for select models. For all these cards just confirm that your camera will accept them, especially for the higher-capacity cards, and read the fine print for the rebate offers.