Lidl will have these kid's wellington boots instore from Thursday 19/09/13 for £6.99, there are quite a few different designs and sizes to choose from too.
Product Information :-
Waterproof and UV-resistant
With removable, warm lining
Insole with aluminium layer for extra thermal insulation
With 3M Scotchlite™ reflective material for improved visibility
Non-slip treaded sole
Sizes: 7 (small) - 2½ (large)