It is not possible to give an answer without a lot more information. The condition of the rifle, that is condition of the metal (blue) and wood (stock). Whether it has a scope or not. Make of scope and type (make of ) base and rings.
A Remington 308 Model 788 is worth about $400 dollars in excellent condition without out scope. Could be less or could be more depending on what I stated in the above paragraph.
Can't be answered without a serial number.
there are 2 .243s in 788 at the local gun shop for $470 each in good shape
What I have found is its 1-10" for 308.
Consider yourself lucky if you get 300 dollars for it.
100-400 USD
1000$
$350.00
100-400 USD
I will first say that the Remington model 788 was made in 6mm from 1969-1979,at this time they are going for anywhere from 250-450 dollars depending on condition.
$500-$600
In mint shape about 450.00--in good shape about 350.00
As with all guns, the value depends on rarity and condition. A 788 in good condition in the most common caliber, .308, will sell for about $300 and up. It has this high value because it was one of the most accurate rifles ever sold, and is still being used by custom gun builders to make target rifles.