Yeah, these kinds of scams come in waves. I saw a bunch of them this week. Often, they're well-established accounts that have been hacked into to make them more convincing. Easiest tell is when they have large inventories, most of the items were added only recently, and/or most of what they're selling is priced much lower than everyone else.
Use the "Report this item" button/link in the listing. Then select, Listing practices, Fraudulent listing, You believe this listing may be fraudulent, and submit it.
When I see one, I usually check what else they're selling and submit fraud reports on several (or more if I'm feeling cranky
![Evil >:D](https://www.eevblog.com/forum/Smileys/default/evil.gif)
). If you're unsure about the typical pricing, you can often see other listings advertised on the item's page. I don't know why eBay doesn't algorithmically flag these already. Maybe they do and they're dog slow doing anything about them until people start submitting negative feedback.