Change of timing belt

Moin, with my moose it drips out of the water pump. Now the timing belt has to be changed. Would be the third or fourth for my car. I definitely had the last one done and now I have looked for parts again and seen completely different offers. What do I really need? The offers go from 80 to 200€. This belt tensioner which is included in some sets, the last time was not there. Should I change it this time?