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.
The maker of your Derringer is no longer in business. Sorry-
10-50 usd
50-100 or so
The Butler 22 caliber single shot pistol was made by Derringer. The Derringer company was founded by Henry Derringer. Derringer pistols are the smallest handguns available and were most commonly used by women.
20-70 USD or so
25-100 usd
$250.00 if in excellent condition
No more than 50 USD
About $250-300, depending on condition.
10-100 usd
About $250-300, depending on condition.
3'000 $