Go to a jeweler and see if he'll price match.

I just noticed that the same is true for oil.
I was also wondering what the red asterisk means next to the $0 entry.

I'd assume it's a technical glitch.

You can buy gold in a variety of currencies. Here's a link to buy from the Canadian Mint. They ship to the US. https://www.mint.ca/en/shop/best-sellers?productSortBy=ReleaseDate