To even begin to give an accurate value I would need to know the condition, maker and model. If you don't know these you can compare yours to ones in the on line auctions, like gunbroker and auction arms. Look up black powder pistol or black powder revolver and compare photos to what you have, that should help identify and give you a value as well.
150 USD
22 cal. dillenger worth
Go to the related link provided below for manufacturer information.
5-250 USD or so
27 grs of FFF Blackpowder.
50-200
a standard cva 50 cal will run you about 100 if you find the right dealer. i got mine for 65 at a flea market
It all depends on the length of the barrel, the caliber, and how much blackpowder you pour down the barrel. A pistol, which is a single shot muzzleloading handgun was around .50 cal and loading 40 grains of blackpowder and a patched round ball shoots at around 750 fps. A revolver, such as the .44 cal Colts and the .44 cal 1858 Remingtons used during the Civil War loaded around 35 grains of blackpowder with a slightly oversized ball, around .451 or .454, can spit those balls at around 800+ fps. The 1847 Colt Walker was a .44 cal open top revolver, but on a much bigger frame. The gun loaded weighed a good five pounds, and it had a larger and long cylinder which held more powder, and could spit roundballs at over 1200 fps. The black powder Colt Walker is regarded as the most powerful commercially manufactured repeating handgun from 1847 until the introduction of the .357 Magnum in 1935, and has a muzzle energy nearly exactly the same as a 4-inch-barreled handgun firing a .357 Magnum.
Impossible to answer without more information.
The value of a Titan handgun 32 cal is $159.99.
100-350 or so
About $50-$75. Rohm, also known as RG, was an inexpensive low quality handgun.