The Marlin model 780 (1985-1988) .22LR is worth in the region of $150-$200 depending on the condition. I own one myself they are a great small caliber rifle capable of good cleen, long distance kills up to around 100 yards using the right ammunition. i would recomend CCI Stingers or Velocitors they are a High Quality, Hyper Velocity Round.
Your Marlin model 780 was made in the year 1987.
Your Marlin model 780 was produced in the year 1977.
Your Marlin model 780 was made in the year 1977 with the serial number that you have provided.
With the serial number that you have supplied,your Marlin model 780 was made in the year 1978.
No records.The Western Auto model 105 .22cal rifle was made twice for Western Auto.The first time was back in the 1930,s and was made by the Marlin Firearms Company.These were the Marlin model 80 and were produced from 1934-1939.The Second model 105 was made for Western Auto from 1971-1988 by Marlin,and these were the Marlin model 780.The age of your firearm should dictate which one you have.
ableammo.com has them for $13