if he can scrape up the money, the cheapest kind of sprocket is going to be the one that he doesnt have to replace for a really long time. i have an iron man sprocket, and while i have heard of it breaking on a 4 stroke, they seem to last forever on a two stroke. i bought my bike as the 5th owner, and my iron man has been on there since at least two owners ago, and i cannot see any visible signs of wear. if/when i need a new one, it will be an iron man sprocket. and yes they do cost in the vicinity of $110 but it could be the last sprocket he buys for the life of that bike.