(MONEY Magazine) – Again and again, MONEY has warned about the dangers of buying out-of-state property (see MONEY, August 1990). The latest object lesson is unfolding in Florida now. It's a whopper, possibly the biggest land scam in the state's history, involving more than 100,000 people who plunked down nearly $1 billion from 1982 to 1990 for acres of inaccessible and undeveloped land, unrentable condos and wildly overpriced houses offered by General Development Corp., a publicly owned company (annual revenues: $580 million). The victims -- mostly from out of state -- ranged from rich retirees to low-income immigrants looking for a share of American affluence (including recently arrived Russians who got their first sour taste of capitalism). According to federal prosecutors, GDC used fraudulent sales techniques and rigged appraisals that inflated prices 500% to 1,000%. The lures included misleading brochures and slide shows. Once they were hooked, many victims were invited on what salesmen privately called ''sohos'' (as in southward, ho) -- trips to Florida at GDC's expense. During the trips, salesmen shielded would-be buyers from outside contacts, even intercepting their phone calls, to prevent comparison shopping. The scam came to an abrupt halt in March when GDC and two of its executive officers, David F. Brown and Robert F. Ehrling, agreed to plead guilty to federal fraud charges. Final details and sentences have not yet been worked out. GDC, under new management, has filed for bankruptcy and promised to pay back up to $160 million. To get even a small slice of that humble pie, victims must follow these rules, as laid down by bankruptcy Judge A. Jay Cristol: -- The 10,000 or more people who were charged double or triple for houses actually worth about $35,000 to $50,000 will have to file individual claims for the overcharges. Send claims to GDC c/o U.S. Bankruptcy Court for the Southern District of Florida, P.O. Box 013391, Miami, Fla. 33101, by Dec. 10. Include the Docket No. 90-12231-BKCAJC. -- The 34,400 or so people who contracted to buy half-acre homesites sight unseen for an average $21,447 each in GDC subdivisions dotted around Florida have been offered consolation prizes, at a price. GDC's new managers have determined that many of the lots are -- you guessed it -- swampland. The company is willing to swap them for usable lots of the same size, mostly in Port Charlotte and valued at a mere $3,500. To get even that, the buyers must waive all rights to file claims against GDC and its subsidiaries. If they don't like that deal, they can file a claim by following the same procedures as the overcharged home buyers. So can the 12,000 owners of GDC homesites who are still waiting for the roads, sewers and water that the company failed to provide. And so can at least 86,200 buyers of GDC homesites in nine communities who forfeited their money by not completing their contracted payments. These would-be purchasers all supposedly had money-back guarantees but were usually told by GDC that ''expenses'' or ''damages'' had eaten up their investments. The lessons: -- Don't buy property without an independent appraisal. -- Check with a local bank if you're skeptical about the price and the payment terms. -- Don't buy from a developer who says your only hope of getting a decent mortgage is from him. -- If you accept a free trip from a developer to look at a property, return home and think about the deal before signing anything.