*When you search an item quality it will show you all items from the quality you picked and higher, no lower.
This is absolutely correct. Whoever said "standard" will return no results is wrong. Setting the Rarity to "standard", the lowest Rarity (and the default setting when you first open the GTN, or if you hit the "reset" button), will generally return many, many pages of listings, including lots of standard rarity items, especially if you don't narrow the level or price range.
It's the other settings (including level and price range) that tend to narrow things too far and get you no results.
Also, as with the tips on mailing items to your other characters, spelling counts. If you're looking for "Lacqerous" Leggings, and spell it "Lacquerous" (or "legings"), or a "Demicot" robe and spell it "Dimicot", you'll get no results.