MOA is about 1" at 100, 2" at 200, 3" at 300, etc.
At 1000 yards, it's a ten inch group, which is still decently small for the 18 to 20" lethal hit zone on most medium live targets.
A 1/2 MOA gun would still hit a 7 1/2" group at 1500 yards - on a completely still day, if the bullet can travel with enough energy that distance.
A gun can be purchased - cheaper than improving an existing one - capable of doing that. Just double the price for the scope - entry level is $3-5,000.
What cannot be bought is the ability to read wind, see through haze, or estimate distance, especially across open terrain thru mirage. That takes dedication and years of practice, hours multiple times weekly at extreme range in all weather.
Start with a couple of good books - Maj Plaster's work should fill in a lot of info.