Now, you just know there's more to tell here.
Did they go off pre- or post-acquisition? Did they just go off whilst the car was sat on the drive? Or is the front end of the car two feet shorter than it was yesterday?
That is a slightly flippant way of saying that depending on what happened to the car depends on what will need replacing. If the airbags have both gone off mysteriously on their own, then you will need to replace them and also find out what else went wrong to cause such a problem. Then that will need replacing too.
If it's been in a shunt, then the seatbelt tensioners will also need replacing, and what about the side, door, and seat curtains?
The SRS system is integrated into quite a few other in-car systems, so they will all probably need checking out. Not a simple job, in my view.