Postal rates rise again on May 12 but consumers can avoid the increase and save money several ways: from online discounts and flat-rate boxes to buying "Forever" stamps now.

The online discounts are new, according to Honolulu postal service retail manager Nancy Wong.

Beginning on May 12, Wong said online domestic discounts will be available of 3.5 percent to 5 percent for people who use click and ship, pay electronically and print out their own postage. She said the international postage will be discounted by 5 percent online, while rates for international express will be discounted by 8 percent.

Flat-rate boxes that allow you to pay one price — no matter what you stuff in them up to 70 pounds — now cost $8.95 to mail and will rise to $9.80. But they will cost $9.30 online, which includes free delivery confirmation, a 65-cent value.

Wong already was a big fan of flat-rate boxes. After all, you can squeeze three 5-pound bags of rice in one of the smaller and flatter boxes. And now there's a new larger one that can hold 50 percent more by volume. The larger box — introduced March 3 — costs $12.95 to mail but online it will cost $12.50. The weight limit on the new box also is 70 pounds, Wong said.

With airlines charging $25 or $50 for extra bags these days, the postal service could end up a traveler's aid as well. Too much omiyage to fit in with your clothes for your Mainland trip? Mail your clothes or your gifts ahead of time so they meet you at your destination.

Those Liberty Bell Forever stamps offer a deal in price and convenience because the postal service sells them at the current postal rate but guarantees they are good forever so you don't have to worry about buying 1 cent postal stamps to cover this year's increase or any future increase.

You could buy them now and still be using them in five years no matter how much the new rate increased by then. "They'll be good for the first-class rate, well, forever," Wong said.

Duke Gonzales, who handles public affairs and communications for the Postal Service in Hawai'i, said 33 million Forever stamps have been sold in Hawai'i since last April when they were introduced.

And he noted that sales of Forever stamps tripled when the May 12 price increase was announced in February.

Even with millions of Forever stamps available nationwide, the Hawai'i office is preparing now for the expected rush of people buying 1 cent stamps on May 12.

Why does the postal service bother with a price increase of just a penny or two?

Because by law the agency can't raise prices by more than the rate of inflation as measured by the Consumer Price Index, Gonzales said.

The reasoning is that "nobody should have to pay more for postage than is necessary," Gonzales said.

However, a change in the postal law in 2006 gave more flexibility to the service and a new schedule that will allow the rate increases to be scheduled each May.

He said that chance is a response to feedback from businesses that it would be easier to budget for increases that come on a predictable schedule.

Gonzales and Wong know that people tend to fall into old habits and expect busy post offices on May 12. So, prove them wrong, avoid the lines and go out and buy Forever stamps now.

Reach Robbie Dingeman at rdingeman@honoluluadvertiser.com or 535-2429.