Put a new timing belt kit on the 3.0 mv6 and for some reason the new tensioner siezed and melted the belt and bent a few valves. Not sure what else was damaged but it not good anyway.

Which would be better/cheaper to do?
Get a good 2nd hand engine or new valves, gaskets etc and fix damaged one?

Alot depends if you can do it yourself mate being honest.
Might be worth getting known good heads with valves etc in too, so you would just need to swap them fitting new head gaskets etc