This discussion is interesting because of the regional variation among other things!
I am a pretty thrifty person, yet I go to a $90 a cut master hairstylist. The reason being that since I wear my hair longer I can stretch cuts out for about 3 months, and most importantly my stylist really, really listens to my needs and cuts based on that. She's as much a "hair therapist" as a stylist!
I also do my own color at home which costs me a whopping $7 every 6 weeks so that offsets the haircut cost. I have used the same mix of professional grade color (LoReal HiLight) for over 10 years and never had a bad result; if it doesn't come out like I'd hoped I will play with demi permanent color to correct it. It mostly costs me time and a few days where my color might be kinda funky but thankfully my job doesn't care if my hair is purple-ish for a week
That said I do think for color that involves highlights, ombre, color correction, going from dark to blonde, covering mostly grey hair, etc. it is best to have a stylist do it. The reason being that even if you save $$$ doing it yourself, you might end up paying $$$$$$ for corrective color.