Hi Rosalie, The cost of a one-ounce USPS postage stamp is $0.55 at the Post Office. If you print postage online, you receive a $0.05 discount and only pay $0.50 for a one ounce stamp. Additional ounces, both at the Post Office and printing postage online, is $0.15. Hope this helps! Eric, Stamps.com Support
As of January 2020, the retail price of a 1 oz First Class stamp is $.55. If you sign up for the Stamps.com service, you may receive a discount when printing your own stamps. See www.stamps.com for more details.
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