Having your hair cut by a junior stylist at Devachan, who gets ongoing training and feedback, is $70. My local Deva stylist (who, I believe, took a 1 day course) is $75. Prior to getting Deva cuts, I was going to a "master stylist" (with curly hair) who charged $45. My hair has so much jump it isn't funny, and the $20 haircuts always made me look like I'd had a bad encounter with a weedwacker.
I was having to have my hair cut every three weeks, because the master stylist's precision cuts would look ragged by then. When I switched to Deva cuts, I was immediately able to stretch that to six weeks (so I spent $5 less in those six weeks), then eight (saving $45 in that timeframe, so starting to see some real savings). At this point, I haven't had a Deva cut in about a year (so I saved $710, minus transportation to and from NYC, but get a day in the city thrown in). I have trimmed my own hair once, using the instructions in (the book and on the included DVD) Curly Girl: The Handbook,
which I already had, as well as some hair shears (from Sally's) to trim split ends, so I'm not counting those costs.