I've done the route by car and it is nearly two hours. You can get the train from Alicante to Denia which takes you right to the centre of the town but I don't know how you would get from Torre to Alicante. Other forum users might be able to help on that bit.

The cost of the train ALC to Denia is minimal - sorry I cant be precise but my friend did the journey in the summer and I know it was cheap, probably under 10 euros. The journey takes 2 hrs 20 mins.