Hello from Thailand!
Woke up early the day of my first flight (Wednesday), worried about entrance requirements. So i logged into onwardtickets.com that has been recommended by other forum members. I booked a flight out three weeks after my arrival, valid for 48 hours, paid $16 by credit card.
I got an email with a flight booking PDF after just a few minutes, and then five minutes later I logged onto the airline website using my last name and the reference number on the booking. Nice! They had a booking under my name.
Just arrived in Thailand yesterday, transiting in Hong Kong. When getting my boarding pass, the agent had a checklist of required items. NO Thailand Pass required, and NO insurance requirement. She did want to see my vaccination certificate and my visa. With no visa, she asked (but did not ask to see) if I had 20 thousand baht or equivalent, and she asked to see my flight out of Thailand.
I showed her the booking email PDF I downloaded to my cellphone, and then the big moment arrived. She logged onto the airline website to confirm and no problem. Done and dusted, got my boarding pass.
Best $16 insurance I ever purchased.