With Today's prices, anywhere from $350 -$450 would be a fair price, depending on condition.
Remington did not make a carbine in .44 Magnum caliber. They did chamber the Model 788 rifle in that caliber. Do you have a Ruger carbine in .44 Remington Magnum, or perhaps a Marlin in that caliber? sales@countrygunsmith.net
Depending on condition, about the same as any Marlin 70 rifle.
Remington
Marlin makes one in that chambering.
A model 336 .35 caliber Marlin in good condition can be sold/purchased for anywhere between $225 - $350.00 (better condition better price).
Marlin
It will vary with caliber.
1988.
remington 740 fieldmaster . 30-06 caliber rifle
remington 725 caliber 222 bolt action excellant condition
5.56x45mm. It is dimensionally similar - but not identical - to the .223 Remington.
Usually a custom job these days.