It depends on which model. It's better if you check the owners manual. If you don't have one, call Taurus, they will send you another one.
It depends on the brand. It might stand for "Taurus Handgun" if it's a Taurus. What brand is it?
The number to Taurus customer service is 305-624-1115.
It is a key operated lock on a Taurus handgun. When the lock is ON, the gun cannot be fired. Go to the Taurus website, and you can see how it works.
100-300 USD or so
50-250 usd
50-350 usd
around $30-40
50-225 USD or so
See the Blue Book of Gun Values
50-200 USD depending on condition.
Used good condition $200.00
100-260 or so