In addition to the luff tape costs mentioned above, you will need to add a leader to the heard of the sail if it not a full hoist sail, sized to make the sail full hoist, and the leader also being taped. If you are going to leave the sail on (usually the reason for the furler...) you should also add a UV cover. Now you have at least doubled the luff tape cost. This work on a 150% with a 50' luff ran about $800.
Certified...in several regards...