Ah – now I understand.
You mean the sellers that have multiple items within one sale, with a drop-down box to select which specific item you want. They sometimes include a dummy item that is cheaper.
Yes, that is definitely search manipulation. No, it is not forbidden, but maybe if enough people complain about it, eBay will change the way that works someday. There is no way to exclude those results. In general, I ignore any results that show the price as a range “$1 – $50”. That means that there are multiple items in that listing.
It is helpful to sometimes select “US Only” as one of the search options. That eliminates virtually all of the trash listings. However, it will also sometimes eliminate the cheapest legitimate options.