Oh, of course, as we saw with prior Nike Albion shirts which could be bought for a little over a tenner from kitwear suppliers, but without the Amex logo and Albion badge.
I'm sure it was just coincidence that the club took iron-on Albion badges off sale at that time and they've not returned...
Sheffield United haven't. Their kit is £45: https://www.sufcdirect.co.uk/home-kit/home-kit
Superphil's post was about Sheffield FC. They are a very small non-league club: http://www.sheffieldfc.com/front-page
They're a little over a tenner here: http://www.dhgate.com/product/new-top-thai-quality-2017-2018-brighton-soccer/400497216.html
I suspect the bloke you bought it from is just buying them in bulk and applying his markup.