SanDisk Extreme III 8GB CF Cards: $4 each
Adorama is selling SanDisk Extreme III 8GB compact flash cards for $57 each. With the $40 manufacturer's rebate, that works out to only $17 each.
But, WAIT! THERE'S MORE...
If you read the rebate paperwork, Sandisk will pay a rebate of $160 (not $120) if you buy three of these cards at the same time. That means three of these cards will cost $171, minus the $160 rebate, for a total of $11 for three cards (that's 24GB of relatively fast memory!). I prefer to look at it as only $4 per card *. You can take a ton of night photographs in RAW mode with that much memory in your back pocket.
They also have similar deals on the 4GB and 16GB versions of this card, although they seem to be backordered on the 4GB and 16GB cards, right now.
* As you may have noticed, I'm a "round it off" kind of guy.