Its not a new deal - they do these all the time - and normally have at least one or two display stands in each shop. However it seems a good idea to mention it as its not really the type of thing those who don't use the shop would imagine they stock.
They come in full frame, semi framed, frameless, and the "fit in a tube" type (also sometimes reading sun glasses). All have sprung legs.
Dioptres are normally 1, 1.5, 2, 2.5, and 3. However - the tube ones are sometimes higher - and occasionally there has been 1.25.
At this price they are cheaper to buy than going back home from the shops if you forget your own glasses.
Footnote: these are entirely overpriced if also available in the 99p shop.