The fabrication costs associated with minting coins make them more expensive. Bars require fewer steps to make and are often made in larger sizes. Given that the labor and machine time involved in producing a smaller product is nearly the same as for producing something larger, it makes sense for larger products to cost a bit less.

These days refiners are focused on making bars that not only cost less, but are beautiful at the same time. "Poured" bars are in high demand from investors today because of the unique look – including the "old school" ascetic.



Gold bars for sale here:
https://bit.ly/2JPLach