Truthfully, Zoro wasn't very good with money. He didn't usually spend much of it, having grown up with very little, and when he did, he just kept throwing wads of it until he'd bought whatever he wanted. Budgeting or investing had never factored into it for him, having a nomadic lifestyle. Fortunately for him, he'd spent years chasing bounties on the most wanted pirates, tens or hundreds of thousands each for most, and it had added up to make him, only coincidentally, a very wealthy man. Sanji was in disbelief when he'd found out how much the scruffy werewolf was actually worth.
"Almost a grand... Is that what these things cost now?" Zoro shook his head. "It doesn't matter," he explained quickly, before Mir got the wrong idea and thought he was trying to talk his way out of the bill. He was sure Mir was giving him a fair price, for more than one reason. "It's just no wonder you always look like you've got the money to burn!"