The cost of the rear shocks including parts and labor is usually around $225.00 to $230.00 depending on make and model of vehicle and what brand of shocks you have put on the vehicle.
However it can sometimes go as high as $350.00 to $400.00 for both shocks to be replaced on the vehicle and then there's taxes which are not included.
So I would get an estimate from a few shops around and it should be between $225.00 to $400.00 for replacing the shock absorbers on your vehicle.
The parts are not all that expensive but the labor is and you might find a mechanic that is willing to do the work in your driveway if possible and they might be able to do it cheaper.
There are mobile mechanics around so if you can't get your vehicle to a shop you can try looking online for a mobile mechanic instead.