At that price I would be both excited and very leery. The locked version typically goes for about 200 euro and the unlocked k model about 230. The old adage of if it's to good to be true.... probably applies in this case.
Make sure of what you are getting - 3770 or 3770k and is it new or used, and if used can it be returned if it is "not exactly as advertised". For all you know, it could be a 3770 that is not fully functional.
Mark