Improve the Free set to actually be useful and best way for that is to add parts that we can use with the previous sets to get better bonuses and have and overall decent set for newer players.
For that make : Hat and Neck +35% Improved Luck with Body and Pants +35 and +30% Improved product drop chance respectively, Belt +30% Experience from jobs, duels and fort battles and Shoes +30% Money from jobs, duels and fort battles.
Clothes set will have 165% Luck, 150% Product drop, 30% Exp and 30% Money. I dont think that is too much to ask for.
Also Animal/Product and Melee/Range bonuses should all be +30%, that way we can combine them with previous items to create something better.