Red's correct - as long as you not intend charging 300€ for an 'uberrare Amiga 500 mil spec' or part out a just recently acquired A4000T plus expansions, whatever hardware you have to offer is worth what someone will pay for it. If you can't get it here, you probably will elsewhere.
I'd love a 3128 for $50, too, but that's no serious way to negotiate.
