I would personally never spend more than £30 on a helmet, small knocks, wear & tear as well as aging of the materials can compromise function.
I think your pretty safe with all certified helmets as long as they fit well, the fancier ones are often priced higher for compactness, weight, ventialtion, style etc.
http://www.bhsi.org/stdcomp.htm
details of all bicycle helmet standards^^
I would personally never spend more than £30 on a helmet, small knocks, wear & tear as well as aging of the materials can compromise function.
I think your pretty safe with all certified helmets as long as they fit well, the fancier ones are often priced higher for compactness, weight, ventialtion, style etc.