King Edward VI Community College student Kirsty Ogborne, 16, suggested police issue 'fixed penalty notices in reverse'.
Under the scheme, youngsters spotted carrying out 'good deeds' will be rewarded with free goods from High Street shops or free entry to a range of local tourist attractions.
The scheme, known as motiv8, was launched on Saturday by street dance group Flava who starred in ITV's Britain's Got Talent.
Kirsty said: "I was really shocked when I found out I had won the competition. I never expected my idea to win, let alone be put into practice.
"I thought it would be good for the police to give out rewards rather than just fines."
Kirsty submitted the idea to the police stand at last year's Devon County Show where the constabulary asked young people to come up with initiatives to promote 'pro-social behaviour in the community'.
Rewards have been donated by AMF Bowling, Apollo Cinemas, Paignton Zoo, Living Coasts, Paignton and Dartmouth Steam Railway and Kents Cavern.
To find out more about motiv8 and how to support the scheme go to www.yrspace.info