The cost of US postage stamps depends on the type and weight of the mail item. As of 2023, the most common regular (First Class) postage stamp, used for standard letters weighing less than 1 ounce, costs $0.58. Other types of stamps and services may have different prices, such as additional ounce stamps, postage for international mail, certified mail, and registered mail. The US Postal Service's website provides the latest information on current stamp prices.