Engine or 'Box mount?

[Christoffer]

My parents got a 2003 toyota rav4 4wd that my brother uses, he's 19 and a new driver - he isn't smooth with the clutch and closes it rather quickly so it doesn't slip but the car lurches.
It's done 35.000 miles aproximately.

I drove it the other day and when I got on and off the gas pedal, the car would 'lurch' og 'jump' in the drivetrain it seems. So the problem is in the transition phases. When you accelerate slowly and then floor it, everything seems normal, and the clutch does not slip at all.

What can it be?? Is it expensive if it's a mount that has snapped?

Thanks very much!