The left front has the most weight.
Shop around. I paid about $95 for the bearing and Sears installed including pressed fit the bearing into the hub. You may not need to buy complete hub assembly when only the bearing is shot. The labor cost was low due to a error on their part. Again shop around but know what your talking about so you don't get taken for a ride.
Now if you install yourself then get complete assembly. Easy to do as mentioned in previous post.