Because you have to sell all this slave items in Noer City = 3/5 free gold from the start + a lot of levels.
 1 Joy Water = 1700-1720 TP which almost = 1 Large Copper Coin (If you don't have WIS stat).
10 Large Copper Coin = 1 Gold Coin (Which means if you take about 50 Joy Water with you that's practically 4-5 gold coins).

What do you need to do?

1) Just keep all Joy Water you can find in your inventory (Take as much as you can carry because it's very expensive to sell) and after that just leave using a raft (Don't forget to take about 10-15 pieces of smoked meat with you which doesn't spoil on the road and some 5 red potions and 5-10 blue potions because you still have to get to the next raft somehow).
2) Go to the next raft which is near the mountains.
3) Along the way collect fish in the swamp forests to feed yourself and use smoked meat only in emergencies.
4) When you get to the mountain raft you need to build it -> for this we need about 10-12 sticks (I don't remember exactly) and it's like 1 stick = 15 STAmina... soo... 150-180 STAmina you need to build a raft -> blue potions and fish soup/smoked meat will help us with that.
5) When you build a raft you sail off the Fishtopia island to the Main Island.
6) Now you need to move towards the city of Noer going into the forests and mountains to feed themselves along the way (Rain Forest and Mountains the best way to get a lot of food).
7) When you get to Noer town then you can only enter the city of Noer through the cave at the north gate because of slave mark (Guards don't like you and some others people too - be careful).
8) Once you're in the cave, you have to get to the hole that leads to Noer's sewer system.
9) When you get out of the sewer, you run all the way to Elise house to remove the slave mark.
10) After removing the slave mark go to the bank and sell all the Joy Water you've collected for no commission.

Welp... that's all. Is it an exploit?