I just posted several deep discounts on a 1 year MSDN Premium Subscriptions and 1 year renewals, but if I was asked the best, cheapest way to buy or maintain an MSDN Subscription, I'd direct any developer to check out the 2 year MSDN Premium Subscriptions.
The 2 year MSDN is part of Microsoft's open license program. It's how Microsoft provides discount for larger orders from larger businesses. What most people don't know is that the purchase price of a 2 year MSDN qualifies a developer for the open license program with the purchase of only one subscription.
Right now, we have a new 2 year subscription listed at $2498 - that's $325 more than a 1 year subscription, but the per year price is $1249 - that's an incredible value.
If you check out our web page on the 2 year MSDN subscription, you'll notice a 2 year renewal listed at $2079. That means the next two years of MSDN could be as low as $1039.50. If you have an existing 1 year MSDN subscription and it's time to renew - you do not qualify for the 2 year renewal subscription. You would have to purchase a full 2 year subscription, but depending on your long term plans - switching from a 1 year to a 2 year could represent a large savings.
Do yourself a favor and check it out for yourself - http://www.xtras.net/products/MSDNPremium2yr/