The most common reason for which Arvin suffered back on earth was that he was penniless. And he always had to struggle for basic things in his previous life because of it. But now as he had a lot of money for which he didn't have to work hard for, made his life quite easier. So he thought that he should reward himself with this expensive wine.
The mana stones were very precious but it was not like that he could not steal them again. He was sure that in the future he would be able to steal some more. And besides, he had no use for the mana stones right now. He needed to strengthen his magic circles casting. And he could not move forwards without strengthening that part. So Arvin didn't think before buying that wine.
