How not to get ripped off on used m1a

This is for the guy that has been interested in a m1a and is ready to buy .This hypothetical buyer is looking at spending 1000 to 1500 bucks .He isn't a competitive shooter just a guy with a job and family and 1500 dollars is a lot of money ,probabally the largest thing he will buy himself until his kids get out of college .He knows what the new springfeilds go for and he has his eye on a couple of used possible deals .Ok experts what does he look for to not get ripped off .i will start with the obvious ,if it is too good to be true it is probabally not true.