This,
You don't have to get one, but it definitely is recommend and less chance of warping or burning your base.
Ski wax irons heat the entire base to the same temp, while a regular clothing iron is very hot in the center and disperses it temperature around the base.
If you use a clothing iron, make sure not to leave the iron in one spot for too long and try to make it so the wax drys about 2-4 inches behind the iron to make sure your not burning or melting the base.
If you plan on waxing all the time definitely pick up a ski iron, quicker and more reliable.