I still find them at blockbuster and futureshop. At blockbuster it was 11 dollars for a yearly subscription so I bought 2. At futureshop they're still 50 dollars =\.
you can but them on eBay or just create an account on the xbox and renew it every year without a card.
Wierd. My local wal-mart has original XBOX gamecards, 12-month and 3-month, for 20$ and 5$ respectively.