My side job is doing a bit of freelance language tutoring online.
My site of choice is Italki (I have a brief review about it here) and I thoroughly enjoy it.
I sometimes get people asking me (either directly or indirectly) if I’d be willing to give any lessons for free, and the short answer is no.
I have a few reasons why:
1) Time: My time, much like your own, is valuable. There are a lot of things in life I am happy to do without asking to get paid (especially if it’s for friends and family, or a charity of some sort), but helping others via Skype with their language skills doesn’t fall into the category of “free”. All of my lessons need time, energy and commitment by me, and I am not able or willing to give any of these up for free;
2) Skills: Much like my time, knowing two languages and also being able to help others improve their language skills takes a certain amount of knowledge, skill and (eventually) experience. All of this has a price tag.
3) You get what you pay for. Be it a language exchange partner (where you both put in your own knowledge and time) or paid tutor or teacher. Everyone wants something for nothing, but at the end of the day you get what you pay for.
This goes for pretty much everything else in life too.