I spent a good month on strategies and research.

One strategy that worked for a little while was: open account at Purse.io, sign up for Amazon prime, buy bullion that is minimally over spot, Purse is "name your discount" so you need for your Purse "discount" to be greater than the premium you are paying over spot. The greatest deal generally would be to buy gold because the premium over spot metal is only a few percent on one ounce and above, but I never got filled on the gold. I made a little money on silver then Amazon seller price premiums went up and the Purse discounts were leaner.

I had the units (Silver Eagles and Mexican Libertads mostly) on hand. I could sell to an eager buyer willing to pay spot metal price and wait for the coins to arrive in the mail. This way, I didn't risk the price of the bullion dropping significantly when it was in transit. The logic was the price of the bullion didn't really matter if I could capture the spread enough times.