You can purchase a Gamo air rifle at your local Walmart retail store. You can also purchase one online from the Amazon website and have it shipped directly to your house.
Gamo never made a Sniper model rifle. It depends on the model, each one is different. You need to locate the model number and ask your question again.
Pyramyd air gun is one of the larges web sellers of air guns (PCP) I suggest you contact them and let them assist you. See the link below
To get an estimate of value you will need to supply more information. Is this and El Gamo made for Daisy airgun Model 126? is this a El Gamo 126 Super Match? Or is it just one of the 30 different rifles made by Gamo? What is the condition of the rifle? Is it working? What is the model number? Giving me the serial number is no help. Re-post your question with more information and I will try to answer your question
You have to be 18 to purchase one
It hard to find information about this line of air guns but I know they were made by "GAMO." I found a magazine add for a new one on the web that was dated 1972
There are several good rifles for hunting rabbits. Crosman, Gamo, Beeman and a dozen other air rifle companies make excellent choices for hunting rabbits. But expect to pay about $150 starting range for a hunting rifle. The lower priced rifles are just for plinking and are not that accurate over a long distance. Purchase a rifle that has rifling in the barrel. Do not get one that is smooth bore like a BB rifle. In fact do not purchase anything that shoots BB and pellets. They are fun but not what you want. Also lean toward the .22 caliber rifles they may be slower in speed than the .177 caliber pellets but they have more knockdown power. This is what you want. I have shot rabbits with a .177 pellet and it just went through them at times and they hopped away and died later. A .22 pellet will take them off their feet. Your choice of pellets is also important. I suggest hollow point pellets by Crosman, Gamo, or Beeman. They deform when they hit a target and will take them out easily and humanely One air rifle I would take a good look at it the "GAMO VIPER air Shotgun" See: ( http://www.pyramydair.com/p/gamo-viper-break-barrel-shotgun.shtml ) it gives you the choice of a .22 caliber pellet or a special air Shotshell. It has plenty of penetration and give you a better chance of getting the target. Do not try to hunt with a BB rifle it just won't work.
pyramydair.com is probably the largest dealer that I know of that deals in air guns. I suggest you go online to there web page and click on "Compare" next to each air rifle you want to know about. The chart will give you all the spec's on one page. This should help you make a better informed decision.
In the USA you have to be 18 to purchase an air gun. But you can be any age to own one. Other countries have similar laws.
If you are looking for a quiet air rifle, then look for one that has a "shroud" on the end of the barrel. An air rifle "shroud" on an air rifle is like a silencer on a firearm only it legal to have one on and air rifle in most places. The Shroud is often called a "noise dampener". Gamo offers the Whisper model that clams to reduce the sound by 52%. There are others that are much more quiet but they can be very expensive. As an example I own an Air Force Condor that has a full barrel Shroud with 5 baffles in the shroud. It's very quiet but expensive, costing over $700. The Benjamin Marauder is also a quiet air rifle with a full shroud at a cost just over $500. I suggest you look at the following web page. http://www.pyramydair.com/s/m/Gamo_Whisper_Air_Rifle_Combo/1275
The age limit to purchase one is 18 but their is no age limit to operate one. This is up to the parent.
There are many places where one could purchase a Simmons rifle scope. The best places to purchase Simmons rifle scopes would be gun stores like Optics Planet.
This is like asking, "IS Ford Better than Chevy?" It all depends on who you ask. I own rifles made by both manufactures and have no preference. It all up to the user. Things I look for in a rifle are how well it is made. I prefer wood over plastic. I like Metal parts. In the last few years I find more and more plastic creeping into the components. Like the Trigger guard. Gamo is known for having a sloppy trigger. But Diana has had some problems. So I suggest reading the reviews on (See the link Below) to see what other people say about the rifles before you purchase one. Also be aware that some models have been discontinued like the Gamo Hunter extreme 1250. It's a fine rifle but no longer made.