Carphone Warehouse seem to be offering PNY Micro Sd cards really cheap.
£3.99 for 8gb - Currently out of stock
£4.99 for 16gb - Currently out of stock
£6.99 for 32gb - Currently out of stock
£12.99 for 64gb - Currently out of stock
I'm not sure if this is online only or also available instore.
I just received 2 which I ordered yesterday. Also free delivery
Also 3 for 2 if you ask for them to be ordered to store (or your home address) via a carphone warehouse store.
Looks like they are all out of stock now. Expired