How much does it cost to mail a 2.4 lb 6x9 inch envelope?

The cost to mail a 2.4 lb 6x9 inch envelope varies based on the mailing service and destination. For domestic shipping within the U.S. using USPS, it typically falls under the Priority Mail category, which starts around $8 to $10. Additional services, such as tracking or insurance, may increase the cost. It's best to check the USPS website or visit a local post office for the most accurate rates.