Lahti1935A,
If you are looking for an entry level sxs or a knock about, you could do better than the Zastava. For a used gun, you might want to look for a Stevens 311 or a Fox Savage or even an Ithaca NID. For a new entry level sxs, I would look at a CZ Bobwhite or a BSA.
If you are hanging around pawn shops, you can on occasion find a hidden treasure. Do yourself a favor and get a copy of the Blue Book and keep it in the car on your pawn shop trips. Besides giving a "ball park" idea to pricing there is a lot of good information.
If you just want "built like a tank" then go to the tank makers. Look for an IZH-43. I have the IZH27 o/u as a knock about for dog training and loaner. Very solid guns. Can easily digest goose loads all day long.
Pete