if you get the non-O from the Thai Embassy in your country before coming to Thailand, there's no need to leave Thailand. The non-O should enable you to open a bank account in Thailand and you can then easily fulfill the rest of the requirements to extend your stay for 12 months.
I never use agents, so I don't know, but I wouldn't have a clue where to start a workaround to open a bank account, therefore the OP might want to look into that as an option. The agents often have contacts in banks and can 'ease' the process. Personally I think their best method is to go to a neighbouring country, but it's up to them.
You were given out of date advice. The problem is opening a bank account inside Thailand, as this is a requirement. It used to be possible, but it seems even agents are unable to open accounts now. You therefore have two options. 1. Fly to a neighbouring country and apply online at the Thai Embassy for that country for the non O based on being over 50, using proof of funds in your home country. 2. Use an agent, but they will likely have to get you an Education Visa first and then convert it to non O later, after opening a bank account for you. The second option is likely to be expensive, as they have a lot of steps to complete.
that probably explains why the price has rocketed. It's really easy to extend your stay yourself, it takes me about 45 minutes in immigration each year and costs 1,900 baht. Good luck.
yes I saw that Graham, the OP will struggle as Brandon explained because he is on a DTV, but Billy said he personally has an account with 800,000 baht and is complaining that the price for an agent to get his second "RV" is 39,000 baht, so I was suggesting he does it himself instead.
instead of paying 39,000 baht to an agent when you already have a Thai bank account and 800,000 deposited, why not do it yourself as it is easy to do? Have I misunderstood something about your circumstances?
you can definitely do it on your own. The Thai visa process is easy. The Thai visa site is not intuitive and a bit clunky, but give yourself a bit of time and be patient and you will achieve it. Once in Thailand extending your stay takes me about 45 minutes in immigration and there's 1 A4 main form to complete (about 15 questions like; name, passport number, date of arrival) plus sometimes a couple of other declarations to sign and providing lots of photocopies etc.
Definitely get the non-O visa instead of OX before travelling to Thailand, because of the reasons Brandon gave. Enter Thailand and ensure immigration stamp you in with that visa. Open a Thai bank account and deposit 800,000 baht in your first couple of weeks. Go to immigration and get their list of requirements to extend your stay for 12 months. Once your money has been in the bank for 2 months, take the documents on the list and extend for 12 months. At the same time buy a re-entry permit, so that you can exit and re-enter Thailand and your visa/extension stays valid when you leave/return. You can repeat the extension every year for 1,900 baht. It's really easy, no need for agents, extending your stay takes me about 45 minutes on average at the immigration office. Good luck.