WordStream's Advanced Bid Changes tool allows you to make complex bidding changes to your selected ad groups and keywords.
Within the tool you can:
- Increase bids by a given percentage or amount
- Decrease bids by a given percentage or amount
- Raise bids to the minimum required by Google to be displayed
- Replace all keyword bids with ad group default bids
You can also place limits to make sure that bids go no higher or lower than specified amounts. Need help with bid management, inquire about our AdWords Consulting  Services