minor fix

Author: bandersmsft

articles/cost-management-billing/savings-plan/purchase-recommendations.md

@@ -28,7 +28,7 @@ The first recommendation value is the one that is projected to result in the hig
 
 ## How hourly commitment recommendations are generated
 
-When Azure recommends and hourly amount for a savings plan, it tries to help you make the most cost-effective commitment. Recommendations are generated by examining your historical on-demand usage. Calculations include any discounts that you might have on your on-demand rates. Usage covered by existing reservations or savings plans is excluded.
+When Azure recommends an hourly amount for a savings plan, it tries to help you make the most cost-effective commitment. Recommendations are generated by examining your historical on-demand usage. Calculations include any discounts that you might have on your on-demand rates. Usage covered by existing reservations or savings plans is excluded.
 
 The first step is to determine the total on-demand charge from savings plan-eligible resources for each hour during the last 30 days. Each candidate amount is used to determine your recommended hourly commitments.