I just would like to know before having it done

Well if you car savvy, you could do the actual replacing yourself the part can cost, on average I guess about $150ish. You can check out this link to get an idea. http://www.car-stuff.com/carparts/infinitig2019921994nsausalt-3059255257.html

Now, when it comes to getting it replaced @ the dealer or auto shop, the prices can range. Your best bet is call ahead and see how much they charge.