That’s kinnda like asking, “How much corn can I get from my field?” It’s near impossible to give an accurate assessment of the guns value without seeing it. Many thing come into play with booth, are the all original? Are there replacement parts from another maker (several different companies made the M1 Garand, parts are interchangeable and many have parts from several different makers) How does the throat and barrel gauge out? And I could go on…..
The make of gun also plays a big part in the value, Winchester is more desirable than H&R or Springfield’s, (they were also made by several others) etc.
You would be best served to take the gun to someone who knows something about them and get an appraisal. Hope that helps.