What is the difference between these two implants?

Eifyr and Co. ‘Gunslinger’ Motion Prediction MR-706
Ogdin’s Eye Coordination Enhancer

Both show tracking speed bonus 6, socket 7 but the ogdin’s is half the price, why?

Simple supply and demand, the Ogdin’s is easier to get, more supply, less price. Ogdin’s is a reward from storyline missions but the Gunslinger is only available from LP stores (and 6% implants are expensive in the stores).

According to eve ref, the gunslinger needs cybernetics at 5, where as ogdins, you only need cybernetic at 3