Lol, sure you just recently bought an iPhone 5C and forgot the passcode . I gotcha.
If you stand on your head and spin around 6 times with the phone and then do a backflip over a sleeping poodle while being accelerated by a discharging fire extinguisher, you will bypass the passcode screen.
I hate thieves and dishonest people that find phones and don't try to return them. Return the phone to the police or an apple store. There's no way you forgot something as simple as a 4 digit passcode.
Kane84. Welcome to the MacRumors Forums. May your time here be fruitful, enjoyable, and praise worthy. Don't listen to the guys above. It wouldn't be 10,000 different code combinations, yet rather 9,999- so at least you've got that going for you.
It would help too if you stated the color of your 5C as the white and blue ones are easier to 'crack' than the yellow and pink ones.