Try e-gunparts.com
50-100 USD or so
For a .50 BMG rifle, $3000 and up, with $3000 being just for a basic, bolt action single shot model.
$50-$100
All firearms that are in caliber .22 Long Rifle (LR) or 22 Long or 22 Short are rimfires. If you look at the face of the bolt, you can see the firing pin. If it is in the very center of the bolt face, it is center fire. If at the edge of the face, it is rimfire.
You need a gunsmith
The Sovereign model SM64 LR in .22 caliber was introduced in 1964. It is a bolt-action rifle manufactured by the Sovereign Arms Company, known for its craftsmanship and reliability. If you have a specific rifle in mind, checking the manufacturer's documentation or serial number may provide more precise details about its production year.
Try egunparts
75-125
Repost with the model number, and we may be able to give you an answer.
1935
$50-$100, depending on condition.
Sign up for a hunter safety course. This should be a single-shot bolt action rifle, about the simplest firearm action there is.