How much does a cv joint cost to replace?? + more

[Mobo]

My car is in the garage and they say one of the cv joints is broken how much should it cost to get it fixed as i dont want to get ripped off.
it also has a few other problems which they are looking into.
Thanks in advance

 

[Mobo]

There is also a leak which they said is from the gearbox seal somewhere.
how much should that be to fix

 

[m0rk]

£150ish