Your parents can give you gifts and inheritances of up to €330k cumulatively throughout your life without you facing any Capital Acquisitions Tax.
So assuming that they have given you no other gifts, this transaction would not trigger a CAT liability for you, but it would knock €125k off the cumulative exemption.
If the house is not their home, then they will pay Capital Gains Tax based on the difference between €250k and what they paid for it originally.
If it's their home, there is no CGT on the disposal.
Not sure about stamp duty but as it's only 1% , it's not material.
Brendan