There is a saying! How much is your head worth? For me only top of the line Arai or Shoei it depends on the type of head you have. Round heads shoeis, oval heads arai. Arai, Shoei, Soumy, and a few others are the only brands I will wear. I have seen cheap helmets split in half before causing head injuries.

Dont skimp on cheap helmets buy you a nice helmet, trust me you will enjoy riding better because the wind noise and fit is so much better. Ok, you spent 5-7 grand on the bike spend 5-800 on a nice helmet. Theres tons of good deals on helmets on ebay, you will find closeouts, or overstock deals.