Renting DVC points are what we are looking into for Oct 2008. We found it would be cheaper with 3 adults and one child than renting 2 rooms at Pop Century. The points vary depending on what time of year and what Villa you are looking at staying in as well as the length of your stay.
To help you figure out how many points you need and during what season, click on this link
http://www.dvc-resales.com/ (don't worry about the fact that this is for DVC resales). Click on the different links on the left for each Villa and it will open up the Points Chart so you know how much you need to rent.
The next step I would highly recommend would be to visit the DVC forums here on the DISboards
http://www.disboards.com/forumdisplay.php?f=7 . Here you can post questions you have on renting on the DVC Planning board. When you are ready to rent points, hop on over to the DVC-Rent/Trade forum (MAKE SURE TO READ THE STICKY NOTES BEFORE POSTING ON THIS BOARD). The price range per point is between $10-$13 and IIRC, tax is included. You can also add the
DDP if you like as well which would be paid in full once you arrive. Both your stay and the DDP have to be worked out with the owner. You cannot call on your own as you are a "guest" of the owner. Park tickets you would purchase on your own and not go through the owner.
You can probably tell I've asked a few questions myself on the DVC Boards to help me understand how this works
