One in "mint condition" was going for $55. And another, complete with striped lawn chair, was "$1,000 firm." But Gloria Medlin was beaming yesterday because she got one for only $45.

These were collectors' items. These were bargains. These were Barbie Dolls.

"This is my speed," said Medlin, 48, of Baltimore, pulling the familiar face and black-and-white bathing suit out of her shopping bag. Medlin's Barbie was missing shoes, earrings and a box. "I get 'em when they're a price I can afford."

Medlin was among the more than 6,500 people who stalked the sweltering aisles of the D.C. Armory during the weekend, looking for Barbies, Kens and other memories at the fourth annual World's Fair of Collectibles, touted as the "East Coast's Most Exciting Sale."

The gathering illustrated the short shelf life of most consumer products. Today's popular buys, it seems, will soon be tomorrow's expensive collectibles.

Ken's cap and gown, still under cellophane, was $45. Farrah, with tumbling curls, was going for $20.

"It's crazy," said Ilene Blankman, 40, an optician from Randallstown, Md., who was behind booth No. 929 with her parents. "Even Indiana Jones. I mean he's not as much, but you can't get him anymore and people buy him."

For $20, collectors could get a Ken-sized Jones that looked just like Harrison Ford, the actor who played him in the movies. But a Han Solo doll from the "Star Wars" films is harder to come by, according to Blankman, so the asking price was $175. Because Ford played both roles, it was the same doll -- in a different costume. But Solo, she said, came with the box.

Most of the faces at the World's Fair belonged to dolls. Their delicate lacy dresses and long locks ruffled in the breeze produced by large whirring fans, which did little to cut the heat or the griping. Next year's show will be in a cooler spot in Gaithersburg, promoter Hubert Bellman promised.

Yesterday's collection of collectors included many experts, such as Rosie Stegmuire, 70, who came by bus from Ontario with members of her doll club, the Dollectibles. Stegmuire was brand-shopping, searching for "Kestners," "Brus" and "Jumeaus" -- the Monets of the doll world -- and consulting her blue book of "Dolls & Values."

Stegmuire would not reveal how much she spent for the latest addition to her collection of 600 to 700 dolls. The 21-inch, closed-mouth Jumeaus go for about $3,600; the open-mouths Jumeaus cost $2,100.

Hoskin Bass from Jacksonville, N.C., travels the circuit more as a hobby and as a chance to get out and see friends. He takes his "toys of yesteryear" to as many as 24 shows a year. He sells "International Barbies" from Japan, France, Sweden and Scotland.

For those not interested in dolls, there was an "Elvis Belt," mounted on a wall in all its leather, silver and turquoise splendor.

There was also an "Assortment of Movie Star Prescription Bottles," including one filled by Natalie Wood in 1979 ($16) and another used by Lucille Ball in 1981 ($15).

"They're from a famous Hollywood trash picker," said Val Wilson, 33. She and her husband Richard, 52, collect and sell such items out of their Chevy Chase home.

The couple was also selling what they said was Humphrey Bogart's suit from "High Sierra" ($3,750) and Fred Astaire's vest ($450). But Richard Wilson was kind of hoping there would not be any takers: "What happens to me is I get emotionally attached to some things."