I'm about half way through my first bottle of Dr. Ron's Organ Delight. Expensive is a relative term and there's not a surefire way to know if you're benefitting from it. You basically need to do your own research and ask yourself if you want to commit to it. You won't see or feel any results by trying them for 3-6 months.
I bought fermented cod liver oil and butter oil as well. Both of those should last 12 weeks.
Another thing you can do if cost is an issue is supplement Organ Delight every other month. Better than nothing and half the price. IMO, alternating supplements and taking time off from them makes sense in a Paleo lifestyle. Keeps you from becoming deficient. And I doubt our ancestors every had access to any nutrient on a daily basis.