Though ammo and reloading supplies are
slowly coming back to the market, there are many, many scam sites still operating. There are many ways to determine if a site is legitimate or not however; in my experience, the easiest way to spot a scam is when they want payment via PayPal, google pay, western Union, bitcoin, Zelle, etc.. When you see this, run away from the site.
Here is a link to ammoland that has an article on this.
Scam firearm sites