You will definitely need an oven. Fortunately, most people have one of these at home already!
But to make it the perfect polymer clay tool, you might want to add an oven thermometer to check that what it says on the dial is what happens inside the oven.
You’d be surprised how often ovens can be 20-30 degrees out. This won’t make much difference to a roast chicken, but it could make a big difference to your clay, particularly lighter colours which will go yellow and burn at too-high temperatures.
If your oven is 20-30 degrees lower than you thought, your clay will look fine but the minute you put any stress on it, it will crumble or snap. Underbaked clay which has been broken is difficult to fix.