Mailing tax return may cost more

Tax procrasinators, take note: Rates for first-class mail weighing more than an ounce -- you know, things like wedding invitations and envelopes stuffed with tax forms -- are a few cents higher than they were last week.

The U.S. Postal Service's latest rate increase took effect one day before millions of Americans rush to the post office to make today's tax deadline. Just one more thing to worry about.  Post continues after video.

• Each additional ounce for a first-class letter costs 20 cents, up from 17 cents.
• Sending vacation post cards from sunny Florida or the snow-covered Rocky Mountains also got a bit more expensive -- 1 cent more, to be exact. They now cost 29 cents to mail.
• Letters to Canada and Mexico, formerly 75 and 79 cents, respectively, are now 80 cents. (For all other countries, it's still 98 cents.)
• You can pick up some new "Go Green" first-class stamps, which, like all new 44-cent stamps, are Forever stamps, meaning they'll still be good after the next rate increase.

Most of the higher rates that took effect Sunday will be felt by businesses. The Associated Press explains:

There will be a variety of price changes for other mailing services, including advertising mail, periodicals and packages, which have complex sets of charges based on size, weight, distance, what percentage of a magazine is advertising and what percentage is editorial matter, and how much of the sorting is done in advance.

Why have rates gone up again? The Postal Service, though leaner and meaner, has lost a staggering amount of business to the Internet and has struggled with the economy and now higher fuel costs. The AP says:

The agency lost $8.5 billion last year and the rate increases -- estimated to bring in an added $340 million this fiscal year -- won't make much of a dent in that. The Postal Service is limited to increases at or below the rate of inflation. A request to exceed that was rejected by the independent Postal Regulatory Commission. The post office, which is not subsidized by taxes, is appealing that ruling, but in the meantime is instituting this increase.

What's next for mail delivery? The Postal Service will press its efforts to close more post offices and cut back to five-day-a-week delivery.

More on MSN Money:

• All new stamps will be 'forever'
• 8 important tips for last-minute filers
• Can't pay your taxes? File anyway
• 5 smart ways to blow your tax refund
• Taxes plunge for superrich