A lot depends on where you are. A lot depends on the home. Certainly 10-20K for a bathroom is not unusual. There are a lot of little things that add up, and labor is very expensive. It's much cheaper to do it yourself, but also takes a lot of time.If you need to ask, leave it where it is.
The old numbers I recall are twenty grand for a new bathroom and forty grand for a new kitchen. Want something special, figure two or three times.
OK, it *can* be a big job, it depends on the house, the extent of the renovation, and the size of DiY projects you ordinarily do.Tom738, it is not a big job, unless you are dealing with a slab or have the structure off of the ground a bit, so that it makes it hard to get under it.