Depends on area, plumbers, how gullible you are etc
I have just had two quotes to do the following:
3 hot and cold taps plus piping to them
1 toilet connection
1 shower connection
All plumbed into existing system (house extension). I admit the initial pipe run is long (9m) but I got the following two quotes
£2,500 and £1,400
I worked out the materials were £600 max which means the plumbers wanted either £1,900 or £800 for what I figured was a maximum of a week's work (I was been generous in my estimate)
Anyway I did it myself and materials ended up costing £376.00 and it only took me a week with my "slow" work.
So on that basis I can see you being quoted anything from £80 to £500 depending on the length of the connecting pipes.