First, find a copy of the owner's manual for YOUR pistol. Second, use ONLY black powder, or a modern black powder substitute, such as Pyrodex. The ROUGH rule of thumb is one half the bore diameter in grains of powder. A .32 cal would use ABOUT 12-16 grains of powder.
How much is a old black powder only 45 cal long barrel pistol worth?
Follow the recommendations in the owner's manual.
Dikar Spain-45 Cal black powder only
10-100 usd
40 grains of fffG
Either FFFg black powder or Pyrodex P may be used.
50-250 USD
10-1000 USD depending on specifics.
10 USD or so
10680
Depending condition, if gold inlay engraving, about 700 to 1000..
Assuming you have a single shot ball and cap black powder pistol, anywhere from $50 to $100. These are modern manufacture reproductions, and relatively cheap.