Shopping still keeps being an annoying task in the web age. The research for what i actually want is fine.

But it is a so damn timewasting and boring experience to sift through all that search results filtering out the non-results and overprized hippster shops first, then trying to find the best matching product on each remaining shop...
They all let you sort by price but not even one offers sorting by price per kilo and only a few offer some sort of product detail filter (which often omit relevant products because of insufficient tagging)...

The last part is rather easy though: compare properties of best matching offers and use the shop with the best offer.

P.S.:
I am fully aware of the fact, that part of the problem is my obsession in buying the correct thing combined with a cheapskate mentality.
So don't comment about just picking the first sorta-matching offer as that certainly would be way too easy (and cheaper because time is somehow money too).