As you have a lot of different options, calculating the cost of your Windows Azure solution seems a complex task. To help you select the right Windows Azure platform offer and estimate your monthly costs, Microsoft launched a new pricing calculator.
The pricing calculator lets you pick compute, database, storage, bandwidth, CDN and Service Bus capacity based on your needs. Along with predicting your expected monthly costs, the pricing calculator then recommends the most cost effective offer for you to purchase Windows Azure platform services.
I especially like the support for multiple currencies and the recommendation it does from the long list of offers.
You can access the pricing calculator here: http://www.microsoft.com/windowsazure/pricing-calculator/.