CORALIE SPARRE, a retired school teacher in Rancho Cordova, Calif., is sitting on 21/2 million unsold post cards, most of them picturing President Ronald Reagan. Don't laugh. She's sunk her life savings -- $50,000 -- into those cards, and all in the hope of teaching America's school children more about their presidents.

But history seems not to sell. Few are snapping up Reagan driving around in a golf cart with Helmut Schmidt, or Reagan on horseback with Jos,e Lopez Portillo, or Reagan and Amin Gemayel smiling, or Reagan pledging allegiance next to Pierre Trudeau, or Reagan waving with the cast of "Annie," or Reagan and Margaret Thatcher squinting into the sun. Don't even mention the card of Reagan patting Vice President Bush's dog J. Fred. What are the wowsers? Nancy Reagan giving Mr. T a Christmas kiss! And the resident eyeball to eyeball with Vanessa Williams!

Dave Schott, who distributes Sparre's efforts in the Washington area, says the card of Reagan and Williams is the hottest seller in town. "We've sold hundreds and hundreds," says John Matthews of Record and Tape Ltd.

Schott says the No. 2 best seller in the area is a card of Reagan staring at Michael Jackson's gloved hand, and Nancy and Mr. T ranks third. Schott, once a government economist, won't reveal sales figures of the hot sellers, though he's comfortable chatting about some of the lesser items. Bob Arnebeck's last article for The Magazine profiled the four first- term congressmen who were defeated in November's election.

From July through October of last year Schott sold eight dozen post cards of Reagan using a chain saw (known in Post card circles as "the Reagan chain saw massacre card"). He sold seven dozen cards of Reagan holding two axes, and three dozen of Reagan splitting wood.

And what card buyers here won't touch is also curious. For example, there have been no sales of the card showing Reagan with a bouquet in front of the Vietnam Veterans Monument, no sales of the Reagans reviewing the coffins of the Beirut bombing victims at Dover Air Force Base, and, for that matter, no sales of Reagan and Elizabeth Hanford Dole at her swearing-in.

Of the 300-plus Reagan post cards Sparre has made, only 92 have found a market in Washington. They sell for 50 cents each, a pretty steep price in a city where other Reagan post cards sell six for a quarter and offer more than enough history for most people.

IT WAS HISTORY that got Coralie Sparre into this business. Just before Jimmy Carter's inaugural, Sparre asked some school children where she taught what the word "Carter" meant. "They thought it meant 'Welcome Back, Kotter' . . . I asked my class what country they lived in and only three out of 30 knew they lived in the United States of America. I wanted to give something to school children so they'd know something about history and politics," Sparre says.

So in 1978 she published her first presidential post cards: a set of 12 of Carter, including the president cleaning fish at his brother Billy's gas station. Then she got the notion of making history while serving history: She published 250 post cards of the Carter years.

"For the first time in history an entire administration has been documented in color picture post cards," the 71-year-old recalls.

She's given 'hundreds and hundreds' away to school children but more than a few Carter cards remain on hand. In the post card business, you can't print just one. At the beginning her local printer's minimum was 4,000. Today, she has to order 7,500 of each card.

She liked the Carters, but her tie to Reagan was even closer -- she'd known him when they were both growing up in Dixon, Ill.

"I remember the last time I saw

him in Dixon. He was in front

of Meisenheimer's Dry Goods

Store in a cut-down Ford

coupe," she says.

The last time she saw

Reagan was in the Oval Office

last February. She was on her

annual end-of-the-year visit to

the White House to pore over

the release book in the photo

office. Every photo the White

House issues is available for

anyone to publish.

After Sparre had finished four

days of research, the White House photo staff threw a surprise birthday party for her, complete with cake and champagne and a chat with the president in his office. He didn't remember her from his Dixon days.

She got a signed photograph from her visit and yes, a post card of same is slated to be a part of the post card history of the fourth Reagan year, except Sparre is running out of money

These days she despairs of completing the first Reagan term.

"I get bitter sometimes that people think so little of their country," she confesses. " . . . If only people realized what these (historical) post cards will mean to children if they bought all the cards and put them away. Today a postcard of Truman is worth $60 . . . You know all the magazines and all the articles and all the newspapers aren't going to be saved. If you have a 3 x 5 photo and a document on the back, well, put it on a postcard and it will live forever."

Her friends around Washington have heard Sparre complain about hard times before. They have a hunch she'll pull through, complete the first Reagan term and move on to the second. History has those inexorable forces and Coralie Sparre seems to have found her place in it.