My Mossberg 500 came with a smoothbore slug barrel with rifle sights. It shoots rifled slugs out to 75 yards with good accuracy. If I wanted a slug gun just to get me into the woods for relatively "cheap", I'd probably go this way. As stated before, rifled slugs are cheap and they do hammer deer.
If you are just shopping around trying to find a good deal on something, I'd be looking for a used Savage bolt action. Quite a few folks buy these and then deceide they don't like the recoil of high performance sabot slugs.