The most common route, in terms of the standard consumer-oriented, national/international option, includes the following companies. Their track record and customer service make them industry standards.
Money Metals Exchange
Options local to you may exist as well. This said, as long as the place you’re purchasing from has a track record, and is verified to ensure the validity of the metals they sell, there should be no significant issue.
The storage of precious metals is a bit more nuanced. It depends on someone’s personal situation, considering factors such as what metals they have, how much, and how safe they want it to be.
Many opt for keeping their gold, silver, or other physical holdings at home. Often in a safe located within their house. Others get more creative, including secret hiding spots or burying it in their yard. Keeping a certain (small e.g. 5-8%) percentage of the metal you own rarely if ever, presents a problem. However, storing most or all of your precious metals at home may be unwise, depending on your setup and situation.
Comparing an at-home safe to an ultra-high secure storage facility, and the latter is usually better in terms of protection from criminals.
As well, using an off-site private vault grants more extensive insurance, and greater liquidity (meaning you can buy or sell quickly).
In choosing a private vault facility, several considerations are necessary. On the insurance side, ideally, all-risk insurance including mysterious disappearances is offered. Then, you need to assure there is no counter-party risk, meaning you can own your assets outright, and it does not exist on the balance sheet of the company.
For this, segregated storage can be ideal for some. Meaning the metals are 100% yours and separate from other people’s holdings.
The costs associated with storage usually include a recurring storage fee (often annual and a percentage of the value of the metals) and insurance (which may or may not be included in the standard fee).
Overall, a degree of thought and research is necessary to ensure you get the right metal, it’s safe, and that this is done for the right price.