Best to take it to a gunsmith and ask for help
Need to know if it is a derringer or rifle.
What is the value of a Davis Derringer pistol magnum 2 shot?
About $250.
50-100 USD
Fairly obscure 22 derringer, made in Germany by World Arms. Value in the $50 range.
Colt woodsman 22, about $500.
I'm afraid that is like asking, "Does a car have a tape player?" It depends on the make and model. Personally, I have a Colt .22 Model 3 derringer and it does NOT have a safety. But, I cannot speak to the many other makes and models.
10-60 usd
10-50 USD or so
10-40 USD or so
20-40 or so