YouTube Voice lessons
If you are going to use YouTube for tips, that's fine for learning purposes, but you still need a teacher or someone capable of evaluating your voice to get you a starting point. If you can't afford lessons, I would try the following:
1. Study the tips without practicing (I like Justin Stoney's New York Vocal Coaching - Voice Lessons to the World, they reflect what I have learned with my teacher.)
2. Find someone to evaluate you - a teacher at a local university or high school, or someone who can give you a trial lesson. You need someone with developed ears who can at least give you some tips after hearing you.
3. Find a friend with reasonable ears.
4. Record yourself and listen to yourself.
If you study the tips, you may be able to kind of get some of it and make small improvements - without a teacher you can definitely work on breath support and your cardiovascular health in general. Without a teacher, you can get started training your ears on other voices and start to learn how to judge your recorded sound honestly. But in order to make true progress, you'll need regular visits with a teacher who can give you warm-ups appropriate for you, let you know what you are doing that is unhealthy or things you can't yet discern with your own ears. Even one lesson every few months is better than nothing, if you can manage that and find a teacher who has an empty slot from time to time for you and can be flexible.