But you think it is a ripoff?
Absolutely.
I could understand
some* trade in say Win7 licences around say 2009, when many businesses might have been buying new workstations but wanted to run XP on them (for the sake of having all the workstations on the same OS, less complication wrt support), but these days?
I've bought such licences on two occasions that I can think of. The first was an XP licence a good few years ago for a customer, shortly after XP stopped being sold by MS and disappeared from shops in general. I was sent through the XP little booklet that comes with a licence, then an e-mail arrived saying "here, try this code", then when that one didn't work, "try this one then". Blatant rip-off.
The second occasion was buying through Amazon (I can't remember if it was third party Amazon seller, I've since stopped buying from them because I've had more iffy experiences than good ones), the Win7 licence arrived and the sticker had obviously been removed then amateurishly stuck back on to the DVD case. Pull the other one, seriously.
* - "some" - big enough businesses would have just requested XP licences in the first place in all likelihood.
I can still buy legitimate Win7 licences for the full, normal price that are still in the OEM envelopes that MS distributes them in (at least they do in the UK), why on earth would I buy one for full price that isn't distributed in the normal way? On the flipside, if they're cheaper (say £20) than the normal OEM copy, then why are they so much cheaper when MS evidently sells them for a specific price? Obvious answer, they're not unused copies.