You would list it in the rentals section of the classified ads because, from the other person's standpoint, you are renting the use for a week, versus selling the timeshare.
However, please be forewarned that RCI's policies - clearly outlined in the Membership Terms & Conditions - strictly prohibit the rental or sale of any week deposited with RCI or any week obtained through RCI.
The penalty for violation of the rule can include suspension of your RCI account, forfeiture of deposited weeks and cancellation of any reservations. That last one is the most troubling. If you rent this week and RCI eventually finds out and cancels it, your renter might show up to check in, only to find that the reservation has been canceled and there is no place to stay. If that happens, you would be in one heck of a legal mess!
Further, we know from past reports by TUGgers and from correspondence received by the BBS administrators that RCI does monitor websites for improper activity.
RCI permits you to recover only the exchange fee and guest fee. Nothing else, no matter what costs (maintenance fees, advertising, etc.) that you incur.
Thus, your best bet, if you can't use the week, might be to find a friend, co-worker or relative that can use the week.
See this post
by RCI's rep to TUG, Madge, for more info on the RCI limitations.