I inherited this rifle recently and was wondering how much it is worth?

It has 4 German Eagles stamped into the receiver along with DAU. It was modified - an old scope was mounted.

You have a Karabiner 98k. The WWII era Mausers were marked with letter or number codes to hide where they were made, while WWI era mausers had the manufacturers names stamped on the receivers.

Marking would be DOU which means it was made at the BRNO mauser factory in Czecholoslavakia- the ones made at BRNO and Oberndorf were top of the heap for quality. BTW, BRNO still makes top notch mauser rifles (CZ).

A complete unmolested (or even un-rearsenalled- the Russians and Yugoslavians rebuilt boatloads of these, and CZ-BRNO built a lot of them from leftover parts for export) rifle would be worth upwards of $500 depending on condition. Drilled and tapped for a sporter scope, they aren't worth all that much unfortunately.
edit:
What kind of scope is it? If by rare chance that its not a sporter scope, you might have struck gold.

As Briman says, a K98k in as-issued condition is a desireable item for collectors. Any alteration made after 1945 by anyone other than German army ordnance people detracts from the value. Unfortunately, there are more altered ones than originals, these days....

Thanks! Unfortunately, it has been 'sporterized.' I had the local gunshop take a look at it.

I plan to use it for hunting - I think these are good rifles.

I always wanted one of those in great condition, and 100% original. But I never did get one. I could have bought a bunch of them back in the 70's and 80's. A long with some 03A3"s. But I did not do it. I guess I made a big mistake........... Tom.