120V to 1.5V

Hi, I recently bought a remote thermometer but it all runs off of watch batteries and I don't want to have to keep replacing them whenever it dies. I was wondering if there is anyway I could take the 120V from my house and convert it down to 1.5v then permenently wire the remote temperature sensor to the house power. I am not totaly in the dark, could I use a plug transformer and get it down to 3V and then use a resistor to kill the rest?

Kill the rest?
Of what the amps?
Go to radio shack and buy one of those adjustable transformers they make.
Then go back a week later when the piece of shit burns up and buy another.