It will probably be something like a Ronda 751, depending on finish and size anything from £6-20 cost price for the new movement. Then its dial and hands off, swap over and ultrasonic clean the case etc. I would also recommend a new crown and case back seal which will only cost a few pounds.
Expect to pay £55-100 depending on where you take it. A decent repair place will offer you the old parts back to show what they have done.