Tie rod ends are generally not repaired, they are replaced. There are two inner and two outer tie rod ends, the cost depends on how many need to be replaced. Please see the Repairpal estimator - http://repairpal.com/estimator - for the cost to replace various tie rod ends on your 2005 Pontiac G6. You should also plan on having a wheel alignment done when the tie rod ends are replaced.
Don't just replace one. you should replace both at the same time. After replacement they should also do an alignment to make sure the car is back on track. I had to do this for mine and all together it was 840.00