Were you driving the car when the belt snapped or was it idling? If idling, you probably have to replace a couple valves but probably no other damage. How old was the belt?
I wonder if that shortened the life significantly.
Pull the head and I bet you will see a couple hits of the valves on two cylinders and that is it. They shut down pretty quick when at an idle. Not much momentum to carry it through a lot of turns of the crank. Might need a couple of valves and you will be good to go. Need anything? I found these after my son visited last month. He ruined the head by placing it on a concrete floor with the face towards the pistons down. But most of this was still good.https://www.dropbox.com/s/3zyahonpv6m89bm/2017-04-16%2018.35.41.jpg?dl=0
I've replaced valves and valve guides and then hand-lapped the new valves to seal properly. As I mentioned before I have also hand-lapped the head gasket surface and actually think that's better than having it milled.
I use a large true flat piece of polished granite and then use some spray adhesive to stick 120 grit paper to it. The paper I use is from an 8" wide floor sander roll. I then lubricate the paper with WD40 or similar. When sanding I vary the direction and position of the head repeatedly. This will not work for a significantly warped head.
If you have a feel for what the compression should be; bring a socket and breaker to turn the engine over by hand before buying.Sounds like a good deal.