price of WireWord ECLIPSE III DISCRETE BIWIRE

Why would you think a private seller would ship you a set of cables for a free trial.  If they are used and you want them then buy them.  If you don't like them re-sell them like he is doing.  These used equipment sites are not Amazon.  

That's a pretty big ask from a private seller.

I agree with @jackd , if you think you want them and the price is right, buy them and give them a shot.
You might love them.
But if you don't like them, put them back up for sale.

see if he will give you a trail period if you pay for them first.

wireworld today makes very well built (if rather high priced) cables

they have a terrific record for quality and good sound stemming back from their start some 20 years ago - to me, their higher value cables are excellent

as many successful cable makers do, they have some very very expensive products for that segment of the buyer market... which i generally avoid 

All of you, thx a lot for the advice. I live in Belgium and the seller lives in the neighbourhood. Just a few miles away. He offered at 406 $, for 2 x 4 M (= 2 x 13 ft) wich seems a bargain to me.  He has also great vintage JBL control monitors on sale (4435), but those are out of my league at the moment. I would pay him of course the full amount while trying the cables at home, he agreed at first, but does not reply any more. I assume he changed his mind.