Don't mind the folks teasing you, it's meant to be good natured.
Plenty of folks here got interested in guns due to games and movies, nothing wrong with that.
The Barret M82A1 with optics and practice ammo is going to run you somewhere in $9,000 range, and is not exactly easy to learn on. It's kind of like seeing someone drive the Indy 500 and saying "I want a car like he's got". It's cool but not really a beginner gun.
If you're curious about it, just run a Google seach on "Barret M82A1", or run a search here on this forum, as we have at least a few folks here who own one and have written reports on them.
If you're interested in getting started in shooting, with an eye to someday doing long-range shooting, your best bet is to get a .22 caliber rifle and start practicing. A .22 will range out to about 100m or so (though you'll want to start much closer in), and is an absolutely outstanding way to build up your skills. Very little recoil, ammo is 2c per shot, decent American-made rifles start around $100 new.
If you're interested in getting started shooting, we have several threads in the Rifle forum right now from folks getting advice on getting started. Let folks know what part of the country you live in, and maybe someone can direct you to a good place to get basic rifle training.
Good luck in tracking down info on the Barret (which shouldn't be hard), and good luck in getting started shooting. Take care,
-MV