Very few of those rifles are worth anything as collectors, you can buy perfectly operational versions for 50 bucks. Some absolutely perfect versions I have seen for sale for as much as 500 bucks, but given how plentiful they are they didnt sell. I have 3, 2 of them are M44 versions with the folding bayonet and one is an M38 (which is exactly the same as a M44 except it doesnt have the bayonet).
The first scope pic is from a M38 sniper rifle, or a rifle made to look like a sniper rifle to get more money out of it. Easiest way to tell is to look at the bolt handle. All of these guns came from the factory with a short bolt handle sticking straight out to the side, which makes it impossible to scope. For the snipers, they installed a turn down bolt handle so the action could be operated with the scope in place. You can do the same thing by cutting the bolt handle and welding a turned down piece on (they sell this as a kit). Even if they bought the bolt, it probably has a weld mark in the middle of the handle where it was cut. An original sniper rifle wont have a weld mark on the bolt handle. You can also take the scope off and look at the mounting, but it may or may not be obvious. I've seen places online that sell a complete sniper conversion kit that has a "sniper" scope, a drill template to tell you where to drill the holes to mount the base, and either a new bolt with the turn down handle or the turned down part of the handle and instructions how to cut yours and weld this part on. They also sell composite stocks for these guns to turn them into a completely modern hunting rifle. I see from your other pics that someone installed a modern scope on the others. I cant tell from the pics if they are M38s or the longer 1891 or the 91/30. These are also pretty much the same gun, but slightly longer. They also have better adjustable sights (IMO) than the ones on the M44 and M38. No matter, they are all reliable, hard hitting and have excellent range and accuracy.
One warning on the ammo. Most US ammo manufacturers make this round, and its not overly expensive. You will find places that try to charge you outrageous prices for it, go elsewhere. Winchester makes a very good round for this gun. STAY AWAY FROM THE RUSSIAN ARMY SURPLUS AMMO! This ammo is extremely corrosive, the powder loads are almost never equal from round to round, and I've heard of misfires several times from others I keep in contact with who collect them. You can often find it at gun shows, and it is dirt cheap. Just say no! The russian ammo usually has Cyrillic characters imprinted on the base, and a red ring around the "cap" in the center. If you do use it for plinking or firing at the range, clean the gun immediately after use. When I got my first one I used the surplus stuff and learned to carry small patches and a rod to run through the gun right there at the range before taking it home, on the advice of some of my collector friends. Then I'd clean it thouroughly at home with solvent.
Good luck with them. Enjoy!