Best small, desktop speakers, $500 or under (new or used)

I have the powered Audioengine 2+ in a gorgeous glossy red finish with a cheap powered sub on the floor. All on closeout and total price under $500. They blow me away with any halfway decent recording on YouTube. Or just everyday spoken voice.
Plenty of exotic mini-stuff out there, but with this setup I am in heaven when working on computer, which is half the day.
Note, be sure to buy the optional stands which position the speakers toward your head. Under $30 if I remember right. 
If it's something you need to look at every day, get these. Endlessly beautiful in sight and sound. And damn near free.

So, did you get enough opinions? You are probably more confused than when you started. The reality of the situation you describe really has no good answer. What is the environment - - -? What volume do you expect to play them at. 3' is really "nearfield" so I assume office. And more important, what type of music do you primarily listen to. If you have to play the speakers at moderate to low volumes, there aren't many inexpensive speakers that do that well. I would suggest making a list of the suggestions in this blog, and see if you can find a place or places near to you, to audition as many as possible. For the past 2-3 years the industry has been turned on it's ear by some of the so called, entry level bookshelf speakers by ELAC. Assuming you are not looking for powered speakers such as AUDIOENGINE, the ELAC B 6.2 currently at $244 /pr. is pretty hard to beat. However there are Wharfedale, and Klipsch speakers in that same price range. You just need to listen to them They all sound different. I'd stay away from used. Or, I'd certainly ask "if your speakers are so good, why are you selling them" ? I think you get my drift.

Totem Kin Mini Monitors. Or anything small from Totem

The Elacs and Wharfedales are great; I mentioned them.

I’ve seen them for sale Used so your argument doesn’t hold up

MAudio BX5s while powered, are a great little desktop monitor. Put out a great tight image with impressive low end. Plus, you can add a sub to them if you want. Great bang for the buck for a powered monitor.