As others have pointed out, Vitamin D is extremely cheap regardless of where you get it if you buy the higher strength pills. You also don't want to overdo it

As others have pointed out, Vitamin D is extremely cheap regardless of where you get it if you buy the higher strength pills. You also don't want to overdo it over the long term. If you're deficient, many doctors will prescribe some large loading doses, but from the studies I've seen, going above 10,000 IU/day over the long term has the potential for hypervitaminosis. Also from the studies I've seen, 2,000 IU/day long-term is enough to prevent deficiency. Lots of people don't like Amazon, but you can get a bottle of 250 or so 5000 IU tablets for about $20. This is enough to last a couple of years at 2000 IU/day. There are few people in the U.S. that cannot afford something that costs $1/month.