So, to Hyuga Shinichi, two pieces of high-purity chakra metal were merely difficult to obtain, not something he could not afford.
Though he was not as wealthy as the daimyo, he could still buy whatever he wanted. Money was nothing more than a string of numbers to him.
As for why Hyuga Shinichi kept taking missions despite already being so rich, that was also tied to the cruelty of this ninja world.
As well as the sense of urgency brought upon him by the three coming Great Ninja Wars.
Ever since learning that he had come to the world of Naruto, Hyuga Shinichi had constantly reminded himself that only by becoming stronger would he earn the right to survive.
After all, he had no cheat-like system or anything of the sort. He could only rely entirely on the mature mind of a reincarnator, his foreknowledge of the future, and Byakugan talent that surpassed those of his clansmen.
So he could only train desperately, take missions, and participate in real combat to improve his fighting strength.
Otherwise, he could have simply stayed in the Hyuga Clan, lived a carefree life as a member of the Main House, and then been controlled by the Infinite Tsukuyomi during the Fourth Great Ninja War.
Without Naruto and Sasuke, he would have become nourishment for the chakra fruit borne by the God Tree, eventually turning into an unconscious White Zetsu...
Back to the point. After Hyuga Shinichi explained things, Namikaze Minato and Shirakumo Hayama accepted the two pieces of chakra metal.
Since Shirakumo Hayama only wanted to forge a single sword, he chose the smaller piece of chakra metal.
Namikaze Minato, meanwhile, needed to forge several specially made Flying Thunder God kunai, so he chose the larger piece.
Uzumaki Kushina showed no reaction to not