Was in Tesco Extra Wigan today and saw this card there (closest match I could find on PNY site anyway)http://www.pny-europe.com/products.php?section=product&categoryid=5&subcategoryid=47&productid=53
With a yellow SEL marked down from £15.27 to £7.97 to £5 each.
From the PNY web they seem to be IRO Class 4 for write. PNY seem to have an odd marketing strategy of colour coding their memory but not actually translating this for the customer in store who wants Class 4 or Class 6 etc.
Quick google finds these at the hi end of Tesco's original (eg £15 @ Play) to about a tenner at best price elsewhere. A further 50% cut off that best price range at £5 a pop c/w 5 yr Gtee ain't bad in my book.