On facebook there is a group for finding substitutes. Usually a person searching for a substitute will post needed days and will post pay rates. Nearly every single comment on every post is about the pay rate discrepancies. In most cases, the substitute will offer something like 110,000 won to 150,000 won for the day (something like 1:00 pm - 9:00 pm). Anyways, most posts will average out to something like 14K - 20K per hour. Comments on every posts are about how the pay rate is ridiculous and should be at the bare minimum 30K an hour. (which I totally agree with, why wouldn't you want higher pay) I asked myself, why the gap between both the employer and employee. Check my basic math, I could be missing something.

On average (of course some are higher or lower) Let's assume an average Native English Teacher at a hagwon, EPIK, private, uni whatever... makes 2.5 million after taxes or 3.0 million after taxes. (people who have been here longer obviously makes more, If I were to pick a random NET and ask them their salary, I assume their salary would most likely be somewhere between 2.2 - 3.2) 

2,500,000 won per month after taxes divided by 160 work hours per month = 15,625 won per hour.
3,000,000 won per month after taxes divided by 160 work hours per month = 18,750 won per hour.
*8 working hours per day multiply 5 days a week = 40 hours per week. 4 weeks in a month, 40 hours per week times 4 weeks per month = 160 hours a month.

If people were paid the suggested amount of at least 30K per hour after taxes.
30,000 won per hour times 160 work hours per month = 4,800,000 won per month
40,000 won per hour times 160 work hours per month = 6,400,000 won per month

I am not sure how the substituting works in Korea, I have never done it, but I am assuming the NET teacher or the Hagwon or whoever owner will pay the substitute teacher. I don't think the person paying the substitute will want to pay more than the pay rate the original NET teacher is making.

My thoughts, the minimum pay rate of 30K or more is usually for tutoring gigs, which I do on the side on top of my day job. I understand if it is urgent and the employer is looking for someone asap, that they would pay more to cover the classes. Most of these substitute posts are usually for future dates, so urgency should be taken out of the discussion.

My Questions...
Are the substitute teacher's that are asking for higher pay per hour equating the substitute gig as a tutor gig? If so what are the reasons?
Are people making 30K and above per hour after taxes at their normal NET job? If so where and I want in.
What am I missing? I am probably not going to respond to questions, all comments even nasty ones are welcomed, I just want to know what people think about this topic. Cheers.

Side notes...
I'm from the states with a masters in social studies education and I taught in the Philadelphia school district for 2 years before coming to Korea. I substituted for 6 months before I got a contract offer and the pay was shit, like 80 bucks a day (2013). Salary was about 60K Dollars after taxes... yeah... another topic for another day. I am married with a kid, working at one of them schools. Also a gyopo, if that changes people's opinions about this post.

As well as what bake said, I don't think working hours and teaching hours should be equated in your math here. No one is working 40 hours a week and teaching every minute of those 40 hours. The substitute is being paid for the classes, not the desk warming time prepping material etc for the year.

Doing sub work in semi-retirement has floated through my mind over the years. I always thought about setting up a site where, if places needed me, I would travel, do my thing for however long, and go home and wait for the next job. I thought it could be a good way to have a look around, and something a bit interesting. I didn't know there was a facebook  group for it. Learn all kinds of things on here!
Anyway, I always imagined 50,000 won plus per teaching hour (with a certain minimum of contact hours), travel fees, and motel accommodation. If places or people are offering anything less, then how do they get anyone to sub?

Yeah, there are plenty of these people around: ''I need a sub for a few days. I make 2.4 million a month so divide that for 20 work days/month, which is 120k a day. I'll pay you cash on your last day''
It's easy to see how this way of calculating is wrong. Let's say someone covers 20 days in a month either at one location, or at multiple ones. So said person ends up earning 2.4 million, while essentially working full time. But that's it, no perks on top of that. No yearly bonus, no health insurance and pension contributions by the employers. No flight reimbursement and no free housing. So it's more accurate to count with at least 3 million instead of 2.4 (and divide that for 20 days)
And then, there is the visa issue. It's not like any random E2 visa holder could sub. legally. And the opportunity cost. Those that substitute are unlikely to do so 20 days a month.

From the other side: the employer wouldn't want to pay more. They already hired someone to work for them at an agreed rate. Why would they pay more than that?
The employee only wants to get away for a couple of days. Why would they need to pay out of their own pocket?

It's not easy to balance both sides. Perhaps a foreign student is willing to take it at a lower rate. I guess one could offer the 150k/day rate that I mentioned above. But if there are no takers, they should be ready to go higher than that.

There are many part-time positions that pay well over 30k/hour. Not tutoring but block hours. With a bit of luck, a number of these positions can be arranged into a full-time schedule. Although, these are not regular NET positions in the sense that an E2 visa holder can't do them. But the work itself is no different from what an E2 visa holder does.

Just curious? Is the OP here the same OP who made the original post in that Facebook group?