I'll be the differential.
A Zorbster is worth more to a man who *actually* wants a Zorbster. See here: https://manchestervacs.co.uk/DysonForum/index.php?topic=123.0
But as for general DC04's, we sell them at £89 delivered see here
. We don't sell them on eBay so that 10% fee is removed. But next day UPS and packaging comes out at about £15.
They sell as fast as we can build them. But as an older machine they often need many parts, and almost always a new wand. So the finished product is as good as new really.
When you are churning out the odd one, you can make money at £40-50. You can pick bits from others and wait on parts for some to come along at right money. But when you can shift double figures over a busy weekend, you need to turn them out, and that means speed, and that means many new parts. So the odd one wants a clutch, a hose and a wand. That guy got a bargain at £89.
When you sell a lot, the odd one may go wrong. You need to make enough to bring a faulty one back here and there, fix it and send it back again. That will cost you over £20 to do.