Health insurance cost is predicated on coverage required, age, existing health conditions. You have to do your OWN research for your personal particulars. Taxes you need to be more specific.
Look at this fellow? Of course immigration is going to question him. You get a DTV you need evidence of money. 500,000 thb. Immigration knows he is not old to be retired, not married, and leaving Thailand and coming right back in? The system was designed to protect Thailand for people like him wanting to stay here longer than legally allowed with no job or income.