WASHINGTON (AP) — The Postal Service is offering $15,000 buyouts to employees in an effort to cut costs at a time when the post office is being buffeted by the recession and the popularity of e-mail and electronic bill payment.

Up to 30,000 employees could take the offer at a total cost of about $450 million, the agency said Tuesday. The post office said it could save as much as $500 million in the next two years.

The agency said it reached an agreement on the buyout offer with the American Postal Workers Union and the National Postal Mail Handlers Union.