I have got same visa from Savannakhet. Yes, it's for 1 year but foreigner must go abroad every 3 months. So this kind of visa is possible for 15 months in fact, no financial requirements but not so comfortable to live.
If you are younger than 50+ y.o. It's better to buy Thai Elite visa: 0.5 mln for 5 years, 0.8 mln - 10 years, 1 mln baht - 20 years. Impossible to work but possible to stay long time.