With the current incentives, the price through Disney is really $93 per point with '06 points included, or $88 per point with no points coming on until '07.
There are no closing costs if you buy from Disney, there will be if you buy resale (several hundred dollars).
If you buy from Disney, your membership will be active in 24-48 hours and you can start making reservations and/or travelling on your points.
If you buy resale, you will put in a bid, the contract goes to Disney for ROFR and, if it passes, closing will be scheduled. The process from putting in your offer to making it into Disney's computer as a buyer can take 6-8 (or more) weeks, and you won't be able to make a reservation until that happens.
When judging price per point in resale, you also need to look at whether the resale contracts come "loaded" with points (banked points in addition to this year's points) or are "stripped" (this year's points already used and maybe some of the next year's points too, since Disney allows borrowing).
That being said, you can save money buying resale if you can be patient, you want to buy at a "sold out" resort, or you want to buy in at less than Disney's 150 point minimum buy-in.