My wife said she wanted a house for 500k baht up near her home in Isaan. The land is already owned, so I'm guessing the budget would be just for material and labor. Any ideas on what kind of house that would buy? I'm assuming it would be quite modest.

Isaan is a large area - so it can vary depending where - but yes, your assumption is most likely correct.

Bht 500k should get her a very modest, local-designed & built one-story ±80-100 square meter [big 2- or small 3-bedroom home, one bathroom] Thai house, with low-budget tile floors, plbg fixtures, fittings & trim, no Western kitchen inside, tile counter & sink out back for a Thai 'kitchen.' ...but not anything an expat would want/need.

NOTE: If builder gets wind of an expat in the picture, double the price.

As said what part of, Isaan, Isarn, Issan, or Esarn is it. there are guys here in that large area of Thailand that may be able to help.

I would say you could get something fairly reasonable within that buget.

Look at homes in that area and get the wife to enquire what local builders are there and who did the work and get some prices, keep your head down. as said inflation will suddenly rocket if your seen.

It also depends a lot on how much you want to have it finished. We were going to have to pay 800k for ours but couldn't afford that. Rather than downsizing we kept the size but had the builder do the footings, foundation, floor, roof, walls and plastering. We will work on tiles, doors, windows etc as we can over the following months. This ended up being 400K. 8x9 meters with 2x4 meter front porch, cement tile roof. 3 Br, inside toilet and kitchen (but we finish counters etc).

I'm also sure it depends a lot on the builder. Some in our area could build for 50-80k less but we really wanted solid work and so we paid more for deep larger footings, larger posts and clay brick instead of cement brick. The builder we chose has a well known reputation as best in this area and actually lives a block away. So far I'm quite impressed with his work. It is still ongoing.

(This is between Sisaket and Ubon R.)