No way to answer without a serial number and complete description
100 USD or so
50-200 USD
No
no, just 45 long colt, what is was made for
It tells the year of manufacture of a Colt.
Derringer 2 Shot, 357 Mag, SN 929, what is the value
Proofhouse.com has Colt sn data.
100-200 USD
Best to take it to a gunsmith and ask for help
50-150
About $300.
value depends on overall condition.................