The reason is very detailed:
The straw hat gang once went to an empty island, where they defeated Enel, who claimed to be a god. The most important thing is that they got a lot of gold, silver and jewels, and then returned to the ground and came to Shuidu, which can be said to be the center of shipbuilding. Many carpenters and Francci joined the straw hat gang in Shuidu.
In Shuidu, Nami, Luffy and Wu took the gold and silver jewelry they got on the empty island and went to the relevant stores to cash it. When the store saw the back eyes glowing, it thought it was the first-class goods, so it immediately offered 100 million Bailey, and then Luffy and Wu's eyes glowed. Wow! A hundred million, a lot of money.
But the people next to me are so very unhappy, so many gold, silver and jewels are only one hundred million? So she told her boss not to lie, pulling Luffy's face and saying that this man is a pirate with a reward of over 100 million yuan, which means that the store should not play tricks. Then Nami offered a price of 300 million Bailey, and finally the boss agreed because he didn't lose money.
See here, you should understand why I said Nami is the most profitable person? If Luffy and Wu were allowed to buy and sell gold, silver and jewelry just now, it would definitely be only one hundred million yuan, and Nami earned two hundred million more. Doesn't that mean she made a lot of money?
Knowledge expansion:
Nami is very concerned about money, because many years ago, Aaron took his hand and came to her hometown-Kekexi Village. Aaron asked everyone there to hand over100000 Bailey so that he could save his life. Nami begged him not to kill his relatives and said that he would give them money in the future. So behind Nami, in order to save enough money quickly, she stole things everywhere and was not willing to spend money at ordinary times. Over time, she is very concerned about money and very stingy.