To disable Bing's auto suggestions when browsing on your Windows Phone 8 device, follow the below procedure:
- Tap on Start > Internet Explorer.
- Tap the More button (a small button with 3 horizontal dots) > Settings.
- Uncheck "Get suggestion from Bing as I type".
- Swipe from left to right on the Start Screen and go to Settings.
- Swipe to the "applications" menu > search.
- Uncheck "Get Suggestion from Bing as I type".