There are alot of listing companies that charge upfront fees just for the privilege of listing on their website. When you talk to them, they will give you the perception that the value of your timeshare is worth more than what it will actually sell for. It is in the grey area as to whether these are scams, but they are certainly less than honest about the prospect of being able to sell for more than market value.
Depending on what you own, there are very few timeshare that is worth more than $1, and many are given away with additional incentives to the buyer, like an additional use year with paid up Maintenance Fees, and also owner covering closing and transfer fees.
You can get an idea of real market value by checking sites like eBay for their Completed/Sold listings.
Why don't you list it here on TUG?