This may- I mean MAY be your rifle. It's a model Marlin Model 49 slide action Shotgun. Exposed hammer takedown combined features of the model 42 and 24. It was never in the Marlin Catalogue. It was made between 1925 - 1928.
The Savage Arms Revelation model 115 is worth $150 in good condition. Revelation was a Western Auto name. The Western Auto is really a Savage 46.
0-150 USD
It is a Marlin Model 49, made for Western Auto.
$75-$150, depending on condition. That is if your rifle is a semi-auto. It would be a Marlin 49. However, Western Auto also had a 150M, which is a Marlin 39A- Value $300-$450
$150.-$300. depending on condition.
25-60 usd
Take it to a gun smith.
10-150 USD or so
About 100-150 USD
If your Revelation 150 is a tube fed semi-auto .22 rifle, it was likely made for Western Auto by the Marlin Company, and is a Marlin Model 49. Depending on the part you need, you may find it at gunpartscorp website, or check with a gunsmith.
50-150 USD depending on condition, accessories, box, papers, etc..
50-100 USD or so