After reading a few tweets on Ajarn.com about being able to survive as a teacher in Bangkok on 30k a month, I spent a little while breaking a few things down in my head.
I came to realise that with the current pay and contract formats being offered, you would in effect be earning less than a full-time corporate Thai employee of a similar educational background, but without any perks.
I'll try and summarise this, although I understand that some would no doubt disagree about some of my comments with regards to what you would call essentials. So, here goes:
A 10-month (the new thing I suppose, and oh-so very popular) 30k a month contract would net you 25k a month over a full year, less if a little tax is taken.
Now a return flight to UK/US will be in the order of 40k if your timing is good. This works out to you having to save 3,500 baht a month, plus 1,500 to have some spending money when you do get home. Not much, but absolutely necessary. So, 5,000 baht a month to save for a trip home. Not too much to ask is it?
So, now you feasibly have 20,000 baht a month. The same amount my Thai girlfriend makes as an accounts person with a BA and 6+ years experience. But she gets a bonus of one month salary or more, so she's already ahead of the game here.
Ok, a small clean and liveable room near to a convenient transport hub will easily cost 5,000 baht a month in Bangers. Please, this is bare minimum. Add to this 2,500 a month for internet, electricity, water and washing machine fees. You now have 12,500 baht.
If you think having a little health insurance is a luxury, then I will forget it, but say 1,500 for this every month and you have 11,000 a month.
Travel to and from work could run from 500 to 2,000 a month (motos, BTS/MRT, the odd taxi here and there) and you could easily be down to 9,000 a month and I haven't eaten anything yet!
Meals (3 please!) at 200 a day for 30 days. This is a basic child-size portion (nowadays) at a food court (50 x 3) plus a drink here and there. So, basic food at 6,000 a month, and you're down to 3,000 a month. Essential groceries to have in a fridge, milk,eggs,butter and bread, some meat occasionally, say 1,500 a month. and now you have 1,500 baht left. Call it emergency fund, doctor/dentist visit.
You have not bought anything. You have been nowhere else in Thailand apart from your classroom and apartment and local shop/ food stall. You have survived on chicken/pork and rice or noodles. You have not had one western meal or other restaurant meal. You haven't bought any shoes, clothes, toiletries or supplies for your hard-up school. You have not had any alcohol and you have not had one night out. You haven't even phoned anyone!
Does this analysis sound unreasonable? I think not. Could you do it every month? But more importantly and appropriately, why would you want to?
I have not given any other negatives to being a foreign teacher in Thailand, as the money side is so damning on its own merits, that it makes me feel woefully depressed just reading it.