Front drivers side wheel - when turning feel a rubbing noise

What is your question?

I know that I need to take this in to be repaired, but I need to know what it is that is causing the noise. When I am driving forward no real problems, but when I am using an on ramp I can really feel it and hear it. Is this the ball joint going bad? About how much am I looking at for cost of replacing both? Thanks for your help.