I'm trying to wrap my head around this. So this person rents RCI points (is that even allowed?) but how do you get access to RCI? Do you already have an account or does he share login credentials? Because depending on what you want, RCI may be tough to use. I have access to RCI through my Hilton Grand Vacations ownership. The RCI inventory is ok, but high demand places to get are either difficult to get, or very expensive in terms of points needed. Are you sure that you *want* to use RCI?
Also I looked at the ad. I don't understand what the $199 fee is for, but here is a link to the fees for an RCI points account in case he somehow gets you set up with an account.
https://www.rci.com/pre-rci/us/en/help/forms-and-fees/pow-member-fees-us I concur with Dioxide - if you actually become an owner, there will be maintenance fees.