Below are steps on how I set up a budget in Azure cloud so it alerts me before I spend too much. I hope this helps you as well.

Sign in to your Azure portal
Search for cost management and click on cost management. You will have a screen like below

Enter budget details
Set Budget name to whatever you like
Set Reset period to monthly to reset the budget monthly as usually you are charged monthly unless you have changed do a different way to pay
Set Creation date to the beginning of the month. This should be set for you
Set Expiration date to whenever you want the budget to end, say 10 years time
Set your Budget amount, this is what amount you are willing pay
My budget looks like this

Click Next after confirming
Set Alert conditions
Select Type of actual or forecasted. Actual means amount of services used and charged for and forecasted means prediction of azure services depending on how you use them. Eg. if a virtual server is on most of the time it's going to predict how much it's going to spend. I prefer actual.
Select % of budget, this percentage is when the percentage of budget you set in the previous screen will send an alert to you. I like to set this at 90%. The Amount will be worked out for you automatically
Action group is set to none
Add Alert recipients emails to who you want alerts to go to
Select language
Click create

Congrats, You have created an alert Now you will be notified when you are reaching your budget and there will be no nasty surprises.

Shameless Plugs

Feel free to comment if you get stuck or have questions or feedback✌️

Happy Coding 🙂 Az 👨🏾‍💻

Create a budget alert in Azure cloud