If it makes you feel good, and happy, then it is worth it What's important is that you love your hair, whether you pay someone 15, 50, or 150 dollars to cut it.
But I agree, you are paying for the stylist's expertise. Can a Deva trained stylist come at $50 a cut rather than $150? Absolutely. I've been to one and she did a very good job. (She was also kind of rude and insensitive, and called the part in my hair a buttcrack, so I'll never go back to her, but I don't think that had anything to do with her prices I think she just had a rude personality; skills wise she was still really good) Can a $150 a cut stylist do a bad job? Undoubtedly.
I think the best thing to do is search out reviews online if you can, maybe talk to a few of her clients to make sure she does a good job, and then take a risk. Hopefully it'll work out, and remember, if you get a bad vibe at anytime, just stop before its too late.

Hope your hair turns out great and you love it, regardless of what you pay. There is no such thing as "too much" as long as YOU are happy!!!
That's me with FSG as my styler!!

3b. fine & thick, coarse, dry, medium porosity. Sucks up product and loves ACVs! FSG is my HG!

Currently using:
Low Poo: TJ's Refresh No Poo: CoWash w/VO-5; Sonoma Soap Company sulfate-free poo
RO: Yes to Cuc; SSC Lavender Condish; Sally GVP LI: Donna Marie Miracle D&C
Style: FSG w/Aussie Instant Freeze & CIAB