Go to the website and you can do some reading about how it works. It's www.disneyvacationclub.com . The minimum perchase is 150 points and don't feel pressured to start with more than that. 150 points will get you about 10 days in a studio during most times of the year.
You can also request a free DVD that explains everything. If you are a big fan of WDW and like to stay in moderate to deluxe resorts, this is a great way to ensure a quality vacation each year for many years to come.
Is it me, or do all DVC members sound like salespeople?