IF there isn't a problem with the toilet flange, replacing a toilet is pretty straightforward. Something a homeowner can do, and many do. If there are problems, then a plumber is called for. If this isn't your only toilet, and you are at all handy, I'd try it myself. If there aren't any complications, it is about a 1/2 hour job (not counting the plumber's travel time). If there are problems, it could be several hours to fix. Depending on where you live, this may also include a permit, and the time to stick around for an inspection, so, not knowing the full details, it's hard to say about the price. The hardest part about replacing a toilet is often getting the old bolts off - they are often corroded. A hack saw or sawsall works to get them off and don't be afraid to break the toilet in the process, since you'll be throwing it away anyway. My unprofessional opinion.