That is not a simple question. To many factors are left out of the equation right now. How big is the shower? What shower jets do you want? They are all priced differently and some are far more expensive than others. How much further do you need to run plumbing? You also need to buy a shower valve that can accommodate the body sprayer function.
Basically a Shower valve pack installed for a traditional shower could cost $1000 parts and labor included.
Body Shower kits with valve, installed with all the plumbing etc. (assuming all the walls from your shower are already off) could run you = $3000 or more depending which ones you want, parts and labor.