Is there a way to prevent billing in Windows Azure trial offers?

There is a new trial offer available for windows Azure which gives you 25 hours of small computing instance time a month and other things like 1 GB SQL Azure and more. See link below: http://www.microsoft.com/windowsazure/offers/popup/popup.aspx?lang=en&locale=en-US&o开发者_StackOverflow社区ffer=MS-AZR-0001P

Now my question: Is there a way to prevent exceeding these limits? I only want to try and don't want to be billed.

I believe you don't need a credit card to use the 30 day pass - the one from here:

http://windowsazurepass.com/

as far as I know there is no automated way to have it turn it off before you get billed. You will need to just be very careful about monitoring your usage manually.

For Doobi's suggestion, I believe you need a promo code to get the free 30 day trial. There is a MSDN blog post with the code MPR001 here.