Hi cent and welcome to the forum.
Frankly, that pipe, in its present condition, is not very valuable even though it looks like it may indeed be a Dunhill (famous brand name in the pipe hobby). Condition and nomenclature means everything in the world of collectible pipes. If that pipe was cleaned by one of our hobby's processional pipe refurbishers (one of the best is our own forum member, Georged), he could then see the nomenclature (stamping) on that pipe and evaluate the overall condition of the pipe after removing the crud and cleaning up that stem. With that information in hand, he could give you a good general idea of current market value. As it is now, there is no information other than the photos which are not flattering.
If you wanted to just let us know what the nomenclature is (the stamping on the pipe), whether you see any chips or cracks in the bowl, whether you see any deep tooth marks on the stem or anything else that does not look right, then someone here may be brave enough to offer you a general valuation while envisioning what the pipe might bring if in good shape and clean.
It is hard to predict in that condition. Properly restored, considerably more than that modest investment! The devils in the details, as pipestud mentions above. It doesn't look like a terribly difficult restoration.