Fabrica de Armas 8 millimeter rifles can go at auction anywhere from $2000 up to $40,000. This rifle was used in the American Revolution and there are not many of them around in good working condition.
It has some value but not to much, this is because they are old but they are not rare. If it happens to be in perfect condition then it would be worth around 500 dollars. Not that much but still better than having a big inaccurate gun sitting around your home.