What happens when somebody releases a super-expensive download on Xbox Live and you don't have a credit card? Logic says you release a new, super-expensive points card to accommodate said people. Logic, in this case at least, is right on the money.
Pop over to Circuit City's online store and you'll see they're already selling 4000-point XBL cards, so you can snag Shivering Isles and a whole lot more for the princely sum of $50.
Source:→ KotakuXbox Live, XBLA, Credit, Cards, Credit Cards, 4000 point, ditii, 451 Press, Microsoft, Online, Store, Circuit City