My (work) imac suffered that problem. The apple store charged AMD something like $384 for parts and labour replacement. I womet how many people suffered the same.
I very much doubt it as majority of that would be the actual cost of the replacement which wouldnt have been at street price (cost to AMD $50 at most and probably more like $5)
Customer receipt may well say some "random" figure, but that wont be what it actually cost AMD to fulfil the order, so its an arbitrary number.