Like buying a new car at a dealership, timeshares sold by developers are pricier than those sold secondhand. That’s because half of the cost of a new timeshare goes toward sales and marketing expenses, which include hefty commissions, says Randy Conrads, co-founder of timeshares reseller ­RedWeek. Roughly 25 percent of the price is the cost of the building, and the rest is developer overhead—and, of course, profit.

On the secondary market many of those costs are nonexistent, so if you’re thinking of buying a timeshare, you may want to consider a “used” one. Dozens of websites feature properties that owners are trying to exit or that resale companies have purchased to sell for a profit. Some timeshares may sell for 30 percent of what they cost when new; others for as little as $1 (excluding maintenance fees). You can even find a timeshare for sale, such as Disney Vacation Club, at a discount.

Then again, the advantage of buying a timeshare directly from the developer can be significant. For ­example, your points can be spent at any resort within the brand family. That’s not always the case when you buy on the secondary market.

So though deals abound, buying a timeshare for sale on the secondary market can be akin to purchasing a used car through an online ad. You might not know if the car was in a wreck or dredged from the bottom of a lake. “I’m not a mechanic,” says Howard Nusbaum, president and chief executive officer of the American Resort Development Association, an industry trade group. “The property might have old liens against it, and I might not know if I’m legally able to buy it.” So before you buy on the secondary market, hire a company to do a title search to make sure the title of the timeshare for sale is clean and the seller is actually the owner.

An alternative to buying a used timeshare for your vacations is to rent from an existing owner. We found bargains at various sites. Using Disney’s Polynesian as an example, we spotted a seven-night rental in early January advertised on RedWeek for $1,785. Had we booked similar accommodations at the hotel directly through Disney, the total would have been $3,200 with tax.

Editor's Note: This article also appeared in the March 2016 issue of Consumer Reports magazine.