Q: pict up and ipod touch at and yard sale they for got the passcde un able to unlock it how can i unlock

If it is Locked with Find my iPhone and you do have the Original Apple ID & Password that Activated it... Then... you will not be able to use it.

Place the iOS device in Recovery Mode and then connect to your computer and restore via iTunes. The iPod will be erased.

iOS: Wrong passcode results in red disabled screen                         

If recovery mode does not work try DFU mode.                        

How to put iPod touch / iPhone into DFU mode « Karthik's scribblings        

For how to restore:

iTunes: Restoring iOS software

If you then see the Activation Lock, you need the previous owners Apple ID and Password to use the iPod

iCloud: Find My iPhone Activation Lock in iOS 7