Citi Prestige = complimentary Avis Preferred PLUS (via MasterCard World Elite).
I read on a blog that you can get complimentary Avis Preferred Plus membership if you called a certain Mastercard concierge number.
I haven't been able to verify this information anywhere.
Note: There is a different between Avis Preferred and Avis Preferred PLUS.
Anyone have more info or actually called the number?