Lidl have got these camping mats instore from next Monday (19/05/14) for £13.99, quite a few colours to choose from too.
Product Information :-
Excellent insulation and air-foam cushioning forextra comfort, whatever the weather
With a large valve for high air passage
Rolls up for space-saving storage
Max (Kg): 110
Size (cm): H5 x W66 x L188