A tractorcade of farmers' wives descended on a Georgetown supermarket yesterday and found to their dismay that it costs as much to shop on Wisconsin Avenue as it does in Wisconsin itself.

"It sure isn't any cheaper," said Joyce Jobgen, who was guarding a a cart with 27 dozen eggs in it at the Safeway at 34th Street.

Peggy Franzen noted that milk cost 17 cents less a gallon than in Nebraska, but otherwise seemed unimpressed, particularly with the processed food. "As far as that ready-made stuff goes, you won't find farmers buying it," she said. "You don't know what you're eating."

The farmers' wives arrived at the store at noon after driving their 57 tractors around the city for nearly two hours under a watchful police escort.

There was some initial confusion over why they had gone to the store at all. "We came to boycott Safeway," said Grace Ashley, a Texan. "I thought we were up here to buy food," another woman mumbled. As it turned out, they were there to accept $200 in gift certificates from Safeway officials as a good-will gesture -- and to spend that and several hundred dollars more restocking for what they say will be a long stay on the Mall.

"They did a heck of a job moving nurses and doctors around in the snow," said Safeway spokesman Ernie Moore, explaining the store's gift.

"Most of the women stocked up on staples like bread and milk, but some were fascinated by the specialty foods the store stocks for local embassies. "I just want the folks at home to know what y'all eat," said one woman while stuffing a can of Japanese dried mushroom soup in her cart. "How do you pronounce this anyway?"

The women, who called the trip a grocerycade, also found time for politicking. "It's a women's liberation thing," said Sue Fry, a Kansan. "I drive this tractor for a living."

Mrs. Billy Thorn, a grandmother from Texas, made her point by stopping shoppers who bought bread and handing them three cents for each loaf from a sack of pennies. The nucleus of her pitch was that "These three pennies represent all we get for the wheat that's in that 60-cent loaf. If we were to get parity, the price would go up only three cents more."

The figure is actually 3.3 cents, according to Agriculture Department spokesman Tom Sand, but Mrs. Thorn received a warm response anyway. "You have endeared youself to the city by helping out during the snow-storm," said Eckart A. Mitzlaff, who returned the three pennies graciously.

"When you first came, I said why don't you go home," said Eloise Gibbs, whose son is a policeman guarding the farmers on the Mall. "But after listening, I figure why can't you get a fair price?"

The reaction to the tractorcade in Georgetown was generally favorable. "Terrific, terrific," said Sam Ferro, who stood applauding on the slushy sidewalk of Wisconsin Avenue. "They've done more for snow removal than the city has."

An angry 34th Street resident who hollered at the farmers' wives for blocking her car was later chastized by her young daughter. "Be nice, mommy," the girl said sternly. CAPTION: Picture, STOCKING UP - Farmer Marilyn Sigwardt dispenses $200 worth of gift certificates to farmers' wives during a "grocerycade." By James M. Thesher - The Washington Post