WASHINGTON — Beginning next week, customers will be able to take advantage of some of the best bargains in the shipping market when the U.S. Postal Service launches new prices for its expedited mail products, Express Mail and Priority Mail.

Effective May 12, prices for Express Mail, the Postal Service’s premier overnight service, will be lower at the weights and in the delivery zones used by most customers. Also, the USPS will offer price incentives for both Express Mail and Priority Mail, its two- to three-day shipping service. Online users and commercial Priority Mail customers will see lower prices, while high-volume Express Mail shippers will get quarterly rebates and price reductions. These savings are now possible due to a recent change in federal law.

“We are excited to offer our customers these price incentives — a first for the Postal Service,” said Gary Reblin, vice president, Expedited Mail. “We already have world-class products and first-rate service, and our new prices make us the best value in the market.”

All Express Mail and Priority Mail customers can save money simply by going online to purchase postage, including customers using Click-N-Ship at usps.com. Express Mail customers will receive 3 percent off the published retail prices and Priority Mail customers will save an average 3.5 percent. Customized contract pricing will also soon be available for large commercial customers.

Also on May 12, guaranteed overnight delivery through Express Mail will be available to thousands of additional locations.

One thing won’t change next week. As always, the Postal Service does not impose fuel surcharges, hidden surcharges or surcharges for residential delivery, Saturday delivery or address correction.