I think that most of the Japanese teachers are 'would-be' or 'self-professed' even they claims they have official license of teaching Japanese. The license never gurantees the quality of their teaching skill, but which just confirms they have attended a private training school for several months part-time. The real professional never appears because they can not live on here italki. 

I-talki is (among other things) a market place where tutors/teachers offer their services and prospective clients are free to accept their services at the quoted price, or not.  If you think a particular price point is too high, then don't go with that teacher.  I have tried seven or eight Japanese teachers on this site.  Several I only used once - they seemed very inexperienced and did not suit my needs.  One was excellent, but her availability was so limited it was difficult to find a suitable time slot.  Another was also excellent, but quite expensive - she was extremely well qualified and experienced but I realised that I wasn't looking for  formal lessons, so she probably wasn't best suited to my needs.  I have now settled on an excellent teacher, extremely well qualified, whose prices are very reasonable and who is a good fit for me. 

I agree with you, but that seems to be normal amongst some languages, you hardly can find informal and affordable tutors for German, it's marketing though, they analyse some facts: Many people want to learn it, the professional ones charge really expensive (compared to other professional tutors from other languages), you can choose the price you want, being that said, the result is no surprise.

Trying differnt tutors is a must, in my opinion. Certificates can be taken into consideration but it doesn't mean that the person has the gift for teaching. But it's quite easy to identify a good teacher just by having a good analysis of their feedbacks. 

There are some tutors who don't correct their students. Indeed, they are charging dor talking to them. I would like anyone to explain to me how useful that is. 

Thanks for starting this discussion, Xavi! 

As a new-to-italki (but not new to teaching English) teacher, it's interesting to hear others' opinions on price and quality on this site.

I will just work on being the best teacher I can be, and also being clear about what I offer so that the right students can find me. As for prices, I am charging less to start out. Maybe some of the more expensive teachers you found already have the students they are looking for?

Anyway, I like your advice about trying out different teachers. Everyone teaches differently and everyone learns differentry so it might take a couple tries (or more) to find a teacher who is your "perfect fit."