What is the cost to replace the O2 front sensor in a 2005 Impreza RS 2.5L? on 2005 Subaru Impreza

Will Subaru reimburse for this cost? I've replaced twice now in 125k miles. What is the expected cost to replace? Also had a transmission linkage problem. Cost me $500.

Asked by for the 2005 Subaru Impreza
o2 sensors are sold everywhere the cheaper ones don't last. use dealer parts only. aftermarket parts are mode to fit multiple vehicle and don't meet specific specs