Driving instructors are wise enough to give you all the tips to pass the test. But you really don't have to bribe them. It's your call though.
When I went to driving school last year, I promised my instructor to give him a certain amount "after" passing my exam. Make sure your instructor believe you.

I gave my instructor QR50 after my exam. He wanted more but I refused. End of the story.

Reality check dude! Would you invest on someone who's a perfect stranger? As my driving instructor would always say "I help you, you help me."

Well, tell your instructor the same thing...he helps you first then only you can help him.

Goodluck, dude!

The ultimate measure of a man is not where he stands in moments of comfort, but where he stands at times of challenge and controversy....Martin Luther King