Just found this, sorry if been posted before, but I think it seems to be quite a good offer, not sure if this is a class 4 card as the picture has the number 4 on?
Save images, ringtones and files on your mobile
High - Speed Data Transfer
5 Year Warranty
With the Play.com MicroSD card your mobile phone will be able to store more images, ringtones, mp3's and movie clips than ever before.
Card has free delivery and quidco.