If the action is in good shape its worth at least $100. There are alot of guys out there (myself included) looking for beat up old Mausers to use the action for a custom build. Especially if its a 1942 or earlier. Those actions are usually stronger and can tolerate higher pressures.
Look up the markings on your old Mauser, half the fun of owning one is learning the history behind it. There should be some numbers and letters on the top front of the action, those will tell you the place and year the action was made. If all the parts have matching serial #'s then you have more a valueable rifle than you might realize.