The masts can normaly be bought on their own. What ever MB want I would pay it, as I had a mast go on my old vovlo. At the time they wanted £30 for the thing so I bought a boggo one from halfords for £10 is broke within 3 months, being stubborn I bought another one (this lasted 4 months) In the end I went off and paid the £30 for the genuine one and low and behold if it was still on and working when I flogged the car a year later