Well, good news and bad. Good? Your rifle is likely a Marlin Model 101, made for Sears under their brand name.
Bad? That rifle has been discontinued for some time now. Another Marlin bolt MAY fit, but they are not drop in parts- they should be checked by a gunsmith for headspace (dangerous if headspace is excessive). My common shopping ground for old gun parts (gunpartscorp) is sold out of these- when they DID have them, they sold for half the value of the rifle.
Best bet will be to check guns show, local gunsmiths. Good luck-
The value of a 12 gauge Sears and Roebuck single shot bolt action model 14 will vary depending on the condition. If the gun is in good condition, it could be worth $150-$200 dollars.
http://www.histandard.info/PDF/Sears%20Shotguns.pdf
This is a Marlin 65 with a Sears name.
High standard
I am also looking for parts for a J.C.Higgins 22 cal Model 43. I need the complete bolt assembly!
75-125
Repost with the model number, and we may be able to give you an answer.
Manufactured for Sears by Stevens, pre-WW2. sales@countrygunsmith.net
A single bolt holds the rear light assembly, you will need to remove this bolt. The bolt is covered by a small round cover (same color as the truck carpet). Use a small screw driver to pop open the cover. Use a metric ratchet driver to remove the bolt. Using a slight amount of pressure on the lamp assembly (fingertips near the trunk opening works best) pops it out. The bulbs twist out of the assembly. Reverse the process to reinstall, making sure that you have aligned and seated the assembly before installing the bolt. There are three pressure fit pins that hold the assembly in place, in addition to the bolt. Make sure that these pins are in place (the snap in) before you rebolt it together. That's it! Takes about 5 to 10 minutes.
It MAY be worth a $50 gift card from Sears. You did not give us the model number, but 583.13 through 583.22 are under a safety recall due to a flaw in the design of the bolt. They are considered unsafe to shoot. Sears WAS exchanging the bolt for a $50 Sears gift card.
10-125 USD or so
The ranger 101.8 is a sears rebrand of a Stevens Model 83 made form 1978 to 1980.