My partner and I have been cutting each other's hair for about 3 years now, the first year was a lot of trial and error but seriously it is well worth it to teach yourself this skill, both of our haircuts are perfectly groomed and we can cut as often as once a week if we like.
Often times the "professionals" don't even listen to what you're asking them to do and the haircuts come out looking like you went to Fantastic Sam's anyway so why not mess it up once or twice while learning. The hardest part to learn is trimming around the ears and neck with clippers once you get that down the rest becomes a little easier as time goes on.
Youtube and Instagram are two great places to see skilled barbers cut hair and learn techniques from them. As long as you make a small upfront investment in good tools and learn how to properly use and clean them it really does work out to be better than going somewhere to get it done.
Both my partner and I receive compliments on our hair and it's fun because we each get to craft a style for each other. Trust your instinct and cut small amounts to start and continue pushing yourself to try something you read or watch. It will take about 6 months before you're truly confident in your skills but it is well worth the money saved and the frustration of having to go to a salon and have small talk with strangers.
It takes loads of patience and it might be better if you learn with a friend and do each other's hair at first so you can see all the different techniques of blending and texturing first hand.