Need help guys, this sensor wire snapped when I tried pulling it off. How do I go about replacing or fixing this? Is it an expensive fix?

 

typical bullet terminals you can find anywhere will fit this temp sender. good practice to cut away any wire that has hard, brittle insulation and replace with new. also replace that leaking distributor o-ring (the most likely cause of the wire breaking) and the oil-swollen heater hose. that's a ticking time bomb.