The oats mixed with grease &molasses/honey/icing sugar is a staple up here. It really appeals to the bears; oats for sustance, smell in the grease and sweet in a sugar based product. Like you mentioned it's cheap but effective. Muchbetter than meat scraps especially when starting the bait in the spring and plug issues! Though nothing wrong with sprucing a bait after it is running with meat scrapes or fish for additional lure.

Yes the grease poured out around is to leave a scent trail for other bears to your bait. Should be freshen up once a week min. Some also add instant powder drink mix or jello to the grease ring.