Apple added the Activation Lock to iOS 7 to combat the rampant unauthorized reselling of lost/stolen devices. There is no way around this lockout? your only options are to contact the person you bought it from and get (1) the Apple ID login credentials, or (2) your money back. If you bought it from an honest/legitimate seller, they?ll help you out. If you bought a stolen device from a scumbag, you are simply SOL, and you now own a pretty, albeit expensive, paperweight.
I love the Activation Lock concept, but it appears to be punishing the unwitting buyer much more than the scumbag thief.
Just enter your password and all is good. Otherwise you have a shiny new paperweight.
You should know the the Apple ID and passcode to get passed the iCloud Activation. If you do not, and if you are unable to retrieve it via Apple forgotten info retrieval process then there is nothing we or you can do.
iforgot.apple.com to retrieve your Apple ID passcode. If you are trying to activate a hot phone you will get no sympathy at legit forums as we all hate phone theft.
If its your apple id, you should be able to reset the password easily from a computer or another device on the website mentioned previously by tomaburque, if you stole/bought hot then sorry, new paper weight.