There are so many variables that answering this question would be impossible. It could be very easy if there was an open ceiling or under floor and very hard if neither was accessible.
The cost will greatly depend on the amount of labor for snaking the conductors into place will take. Will you accept exposed conduit or will you require everything be canceled? Will there be a lot of furniture and appliances that will need to be moved in order to access the space needed for this installation or is it all open walls?
Then there is always the issue of the calculated load on the service. Is the service large enough to add another 1500 watts to it or will it now require an upgrade?