It seems as if this is a moving target, as last year we had several confirmations that new members were allowed to purchase 50 point contracts. Now it seems that the minimum for new members is 100 or 160 depending on the resort. However, I am not sure if these minimums are simply advertised and not enforced. Over the years there has been a lot of inconsistency between what different salespeople will do, so I'm wondering if you threatened to walk, would your salesperson make a 50 or 75 point contract happen for you as a new buyer.
I find a great source of information for prices and minimum purchase prices can be found here:
http://www.dvcnews.com/index.php/dvc-program/financial/pricing-a-promotions