Point out to her that a top of the line whistle is still a LOT cheaper than even a modest instrument of most other types such as violins, pianos, flutes etc. I can’t think of any other instrument where, for a few hundred dollars, you can have a craftsman make you a one of a kind instrument which, with a little care, will be a lifetime investment. Long after the cost is forgotten, the whistle will bring pleasure and satisfaction to you and, hopefully, your listeners.
I agree with Paul.
I will play my whistles for the rest of my life. No other instrument, no matter how much it is respected, produces a sound I like better, not even the flute.
So, whether or not to spend $350 for a hand-crafted, individually-tuned instrument that you will play for years and years is really a no-brainer.
Do it.
If you don’t, your car will break and you’ll have to spend the $350 on THAT!!