ListClean offers a pay-as-you-go pricing model based on the number of email addresses verified. The pricing structure is as follows: - The first 100 email verifications are free. - For 10,000 email verifications, the cost is $5. - For 1 million email verifications, the cost is $145. The pricing follows a tiered structure, with the cost per verification decreasing as the volume increases. For example, the cost per verification for up to 10,000 emails is $0.0005, while for up to 1 million emails, the cost per verification is $0.00014. ListClean also offers volume rates for larger organizations, with pricing available upon request for verifying over 5 million email addresses. It's important to note that ListClean does not charge for "unknown" results or duplicate email addresses, ensuring that users only pay for verified results. Additionally, the credits purchased or received as part of promotional campaigns never expire, providing users with flexibility in managing their email verification needs.