The cost of saving the whales is going up.

So is the cost of saving Jesse Helms, keeping the American Red Cross afloat, getting a shot at $10 million from Publishers Clearinghouse, and ordering a sweater from L.L. Bean.All of these depend on third-class mail - known to the public as junk mail - and people who use it for their livelihoods are complaining that the recent proposed increase in U.S. postal charges are devastating to their business.

While first-class mailers are seeing a 16 percent increase when the price of that stamp goes up to 29 cents, third-class mailers say they are seeing an average of a 25 percent increase and some types of mail will be going up 40 percent.

The Postal Rate Commission, which recommends rates to the Postal Service's board of governors, decided that third-class mail should carry a greater burden of this year's increase.

The governors will vote Jan. 22 on whether to accept the commission's recommendation, and it is expected to pass.

"People can't help but go out of business," said Lee Epstein, president of Mailmen, Inc., a New York-based company that helps third-class mailers with the Postal Service. "These businesses are marginal, and the bottom line is gone."

For people who hate junk mail, this is good news. The amount of unsolicited mail will drop, experts said.

The increase will boost the cost of many political campaigns, say political consultants. Many candidates rely on direct mail to raise millions of dollars to pay for their television advertising.

But the Postal Service may actually lose money by raising the third-class rates so high.

Nearly 40 percent of the 165 billion pieces of mail the Postal Service handles is third class. And third-class mail generates billions of pieces of first-class mail every time someone responds to a solicitation.

But the annual 3 percent growth in third-class mail leveled off after the last 25 percent rate increase in 1988. Now many experts are predicting it will begin to drop after this new increase.