If you are looking for a Rolex watch, then you are ooking a genuine Rolex, not a cleverly constructed fake (or blatant rip off). Unless you have lots of money to spare, you are probably looking for a good used Rolex watch as buying these luxury watches used can give you a great discount without sacrificing quality. Obviously, only reliable sellers sell authentic Rolexes. Legitimate Rolex dealers would never attempt to sell a fake, passing it off as an original. In fact, only authorized Rolex dealers are legally permitted to sell genuine Rolex watches according to the official Rolex website.
This does not necessarily mean that all unauthorized Rolex dealers selling Rolex watches are selling Folexes (fake Rolexes), although it is a distinct possibility. Genuine Rolex's may be available at auction sites such as eBay.com, and as some sites say, may be bought from the wholesale secondary market, with savings passed on to the buyer. Still, it is a shaky business deal and one definitely worth researching. The Rolex Company is notorious for demanding its dealers are authorized, and even its repair centers be authorized. The company is also known for not selling Rolex parts to anyone else.
This site not only has a list of reputable dealers and repair centers, it also has many helpful links directly related to Rolex sales and tips on buying Rolex watches. It also draws attention to a Rolex price list, a serial numbers reference, and Rolex forums, visited frequently by Rolex experts.
Another valuable piece of information is the "The Rolex Report" a book by John E. Brozek, which includes research, references and insider tips on detecting genuine Rolex watches from fakes.