Any time Peridot spends exploring the sunken ships is going to be spent largely with Amethyst. She doesn't really care much about money so much as she mostly just has her eye out for interesting knick knacks and bits of shiny stuff she can use in her art projects, as well as any salvage that may be useful for bringing back to the carnival. The key advantage she has is that she can use those metal powers of hers to help extract hard to reach treasures (obviously provided they're metallic). Most of her free time in Atlantis will be devoted to doing this.