Shes not "easy" to get MOC...none of them are of course. And in honesty she doesnt show up too often at all..but personally for a slightly warped card, I think the $125 to $150 mark is fair...$175 seems a touch high in this market. Just because she doesnt show up often doesnt mean she is worth more [there is a massive difference between sought after and rare] - not every one is in the market for MOCs.
But if she is a grail and you want her there is no harm in paying whatever you want to. Good luck whatever you decide!