The best way to buy is online, from the lower priced dealers, which are SD Bullion and Silver.com. (I think SD Bullion is based in Michigan, by the way.)
But right now is bad time to buy retail physical silver. The premiums are unacceptably high because of an explosion of demand due to the pandemic. I would wait a few months for premiums to normalize.
If you want exposure to the silver market right now, I would buy silver ETFs or OneGold, which offers silver as well as gold. That way you don't have to pay the insane premiums.
PM is precious metals, as noted above. Another major acronym is ASE, for American Silver Eagle, and AGE for American Gold Eagle.
ASE have higher premiums than Maples, but they tend to hold their value pretty well. I like Maples too – very high quality, good anti-counterfeiting features, and 9999 fine vs. 999 for the ASE. Note that the 2021 ASE will have new anti-counterfeiting features too, finally. Another good reason to wait a few months...
Libertads have the highest premiums of any mainline silver coin. And they're hard to find. I haven't seen 2020 Libertads anywhere. You'll often see the 2 oz size more than the 1 oz.