Since most things I buy from amazon are commodity type items I need quickly and cheaply, my method has been "Prime Only" + "Sort Lowest First". Add on a score minimum filter if the first results are junk.
If you're just looking for something that's all whitelabeled stuff all coming from the same alibaba source, you can just find who's selling the same thing at the cheapest price currently. The prime only label is needed to filter out the stuff with extreme shipping pricing and times selling for $1. Would be much nicer if they could just properly sort everything with shipping included like ebay but whatever.
The results have long been flooded with brands with names like XEZAXFE all selling the exact same thing so it's the fastest and easiest way to find what I'm looking for if it's not brand name (which I wouldn't trust amazon to send me a non-bootleg version of otherwise if I want brand name).