Might be Winchester.
500 USD
Need to know the exact model to answer.
Ithaca 500 model shotguns were imported by SKB (japanese manuf.). They are currently selling on gunbroker.com for $600-$1200 depending on condition.
A marlin model 36 with the A prefix to the serial number is the 3rd model,of the marlin model 36 and made from between 1946-1947.
Manuf. or man.
If you call Colt with the sn, they will tell you.
$300-$450 depending on the condition. Based on a Mossberg 500 and manuf in 1973
Try the sn tables at Proofhouse.com
Proofhouse.com has Colt sn data.
100-400 or so
This gun was made in 1949.
if under warranty its best to use manuf spec