you have two options to get a 90-days Non-Imm-ED (education) visa:
*** apply for it in your home country before you fly to Thailand. You will need documentation from the school or university you plan to attend
*** apply for it on Immigration inside Thailand. This process is called βchange of visa typeβ from a 60-days visa-exempt entry or from a 60-days Tourist Visa, to a 90-days Non-Imm-ED Visa. Also done with documentation from the school or the university
Under both options, the airline CAN ask you for a proof of onward travel out of Thailand within the period you will get stamped in, if you show them a one-way ticket at the Check-In counter
you don't "extend my visa". A visa cannot get extended. The visa you used to achieve the "extended stay permit" has become invalid already. Immigration just extends a stay permit. The stamp you receive in your passport clearly states that you got a stay permit and not a visa. A 1-year stay permit based on reason "Retirement" . . . and for this stay permit, you can buy a "re-entry permit". This re-entry permit has a validity for use until the expiry date of your extended stay permit
single re-entry is 1000.- THB, a multi re-entry is 3800.- THB. At the Airport if you haven't any prepared forms and pictures, you will need to add 200.- THB to these fees. Why I take a notice? I got my own visa advice group, I just can't allow myself to hand out incorrect information π
in the e-visa menue, you need to look underneath Non-Imm-OX and Non-Imm-OA . . . there it will say "other". Just click onto it and all the other Non-Imm-visa categories will open
actually what you wrote in the first part is inconsistent with the facts . . . "travellers milking visa-exempt stays" in reality are the ones that are asked to stay for 2 nights. In "all likelihood" he did a visa-exempt entry, or he wouldn't have received an "exempt entry stamp" for it. So much for sounding inconsistent when re-reading π
if you don't value this wonderful opportunity and can't afford to pay these meager 24,000 US Dollars into your Thai bank account, you shouldn't be in Thailand
"Financially it makes sense to keep the 800 in investment rather than rotting in a thai bank account." . . . . . you seem to belong to those expats who are supporting corruption in Thailand. And you seem to forget that the 800,000 THB in a Thai bank account actually earn a very good harvest: They are the "parking fee" that enables you to live in a country on half the monetary expenses you would have to pay in your home country