The reason you enter Thailand determines the type of visa you will need. I am guess by the question you will require a tourist visa. The requirements for tourist visa vary depending on passport (nationality). Tourist visa are short lived (60 days or 90 days or something, depends on your nationality). If you are looking to stay longer (years) then you will look for long term visa, those are generally "Non B" or 'Non O' visas. They are issued for: retirement, dependent, work, marriage. The other long term option is the elite visa which starts at/about $15,000 for 5 years.
Good luck
Correction and explanation. "Non B" stand for "Non Immigrant type B" and "Non O" stands for "Non Immigration Type O". The B visa (Non B ) is for business related activities (work Investment etc). The Non O is for something else which includes retirement and marriage... I am less familiar with the Type O, and not currently familiar with a Type B (I may actually be on Non B, but the agent worked it for me so I am pretty clueless).
The larger point is "Non-XXXXX" Is not like it sounds.. It is actually "Non Immigration Type XXXXX"
I have never used my KTB debit card for online purchases. I tried once before and wouldn't work, something to do with going down and talking to the bank. There seems to be different levels of 'open'. I am able to pull funds from the ATM internationally with my KTB debit card, I remember telling them I needed to use it internationally, but I guess online is a different thing.
My US credit cards mostly work locally. Often times the original charge will decline, I will get a text to my US number asking me to verify then the vendor has to try the transaction again.
Sometimes it just does work. The mastercard will but the AMEX wont and visa versa.
I did the the back-to-back tourist visa thing. They are similar costs, provided you will avail of the total duration of the visa (5 or 10 years). The cheapest method of back-to-back tourist visa is probably about 400 - 500 year. I dont think anybody wants to do this (bus to nearst border spend the night get visa come back).
I elected to travel to different places every time I needed a new visa (Vietnam, Australia, India etc). Definitely more that $1,500 a year. But then again - I got to see more of the world.
Same boat. Currently on Volunteer visa. That will expired sometime early next year. I will see what is available then. I have been doing back-to-back tourist visas that worked for a few years.
cheap ticket may include Kuala Lumpur, Seoul, maybe HCMC. You can find cheap deals. Never mind time/destination - you wont be using it anyway. Just have to show evidence you have 'plans' to leave. Another option would be for a few bucks more you can upgrade your current flight that will allow for cheap rescheduling.