(MONEY Magazine) – For thousands of McDonald's junkies, it isn't the Big Mac or even those crispy fries that keep them going back for more. It's the toys. Sure enough, the palm-size trinkets that accompany each $2 to $4.50 children's Happy Meal have become a megasize craze since they were introduced in 1977. The fast-food giant continuously releases new toys not only in the U.S. but in 79 other countries. Some vintage McToys are now collector's items, fetching premiums as high as 8,000% (trading for about $80 now, vs. an original value of $1 or less). Few collectors seem to be in it entirely for the money, though. Says Joyce Losonsky, 49, of Columbia, Md., who owns 6,000 Happy Meal toys: "We do it because it's McFun."

Hot: Regional and international toys; those marketed for ages three and under; early Happy Meal boxes or bags (which hardly anybody thought to save)

Not: Educational items, such as a 1991 ecology book

Entry level ($1 to $15): Most U.S. issues featuring popular cartoon characters

Mid-range ($15 to $100): Toys from the early '80s for kids under age three; any that appeal to other collector groups, such as the 1979 Star Trek communicator

High-end ($100 to $500): Early boxes, bags and counter displays; rare mint-condition sets with a complete series of toys in their original packages

Prospects: International and regional toys should appreciate the fastest, if only because they're more difficult for collectors to get. Odds are slim that new U.S. issues will gain much value, since so many people are hanging on to them.

Where to buy (besides McDonald's) and sell: Swap meets and auctions sponsored by the McDonald's Collectors Club (417-781-3855); ads in the club's monthly Collecting Tips newsletter (12 issues, $23.95)

Resources: Tomart's Price Guide to McDonald's Happy Meal Collectibles (Tomart Publications, $27.95); McDonald's Happy Meal Toys (Schiffer, $24.95)

--Karen Hube