Root canal can be done by either a General dentist or be referred to an Endodontist specialist. Normally you would go to a General dentist first and if determine that you should see a Endodontist the General dentist will refer you to one.
The dentist will remove the inflamed or infected pulp that is in the inside of your tooth. Then the tooth is filled up and sealed. If you went to a endodontist dentist for the root canal you would return to your general dentist for a crown. The crown will help to protect your tooth and restore it back to full function.
Though having a root canal and crown work can be costly, (Though if you have dental insurance these types of dental services are normally covered to some degree) most dentist will advise this procedure in order to save a tooth.
Some people feel that having an extraction would be less costly however that is not the case if you are wanting to replace the missing tooth pulled. Leaving gaps in your teeth due to pulling is never a good idea because shifting of your remaining teeth will happen over time.