2002 Jeep Cherokee

My 2002 Jeep Grand Cherokee steering wheel will shake sometimes when I put on brakes. Sometimes very badly (depending on the speed I have) and sometimes just slightly. Sometimes it does not matter the speed, but I notice that it does matter the road because it does not do it all the time. And because I travel the same roads all the time, I can generally tell when it will do it. Also on these particular roads my wheels seem to do a lot more
shakeing themselves. I just feel them a little more than at other times.

I had a mechanic tell me that it was the front rotors on my brakes that needed to be rotated and that I needed a wheel alignment and/or balancing and rotating.

Before going out to get these repairs, I want to make sure that could be the issue and about how much should I be expecting to pay.