First, I'd like to point out that this is not an off-center strike, as NGC has noted on the label. It actually appears to be a major (and I mean major!) misaligned die. This may be an oversimplification of the error attribution, but it is not a simple off-center coin. This is another good lesson in error collecting - always scrutinize the label!
Others have provided good information about pricing.
There are many variables such as eye appeal, severity, rarity, host coin, etc., that contribute to the value of the error.
Many error dealers and collectors will learn precisely how these factors contribute to value over time and are able place a value on an error coin. Of course, because many error coins are unique or nearly so, there only needs to be one collector to drive prices sky-high.