For an circulated penny fron the 70s that's 2%-5% off center how much money is it worth to a collectors? And should I keep this penny at that.
Photos would help. Is the coin truly off-center or does it have a MAD (misaligned die)? In general, a coin that is only slightly off center will not command much, if any, premium. When the coin is off center enough that parts of the features (letters, date, design features) are missing it will be of interest to error collectors and worth a premium.
OK, so it is not off-center. And I assume that only one side is affected. Very little to no premium unless a portion of the design is missing in which case very little to some premium.