With new issue of contaminents in water and fish farms popping up all over the world, I would not be taking any fish oil unless I knew where the fish came from first and foermost. And as mentioned, buying in bulk can save money, but it still comes back to where the fish are coming from, and since most are farmed fish in recent years to keep costs down, fresh open ocean fish are becoming more rare every day.
I use to use fish oil for omega 3 benefits, but no more, there are better sources for omega 3 without the concerns of unknown contaminents, and with fish farms feeding GMO corn, never mind the antibiotics used in feed to prevent disease when fish farming, just too many open questions these days about all the fish we eat, never mind fish oil supplements. Hemp oil is what I now use for quality omega 3 supplements, and with the hemp industry growing every day, the prices will come down well below the best fish oil supplements.