Great for

• Tracking AdWords and Bing account spend and adjusting budgets month on month depending on previous months spend
• Adjusts budget targets by moving over/underspend from one cycle to the next
• Detects and adds newly created campaigns to Shape budgets
• There is no user limit, you can add your entire team to your Shape account
• Create automated alerts to inform you if you account is under or over spending

Be aware that

• The free tier is limited to tracking the budget of 1 account