I went to the Ban Phu Nam Ron border crossing with Myanmar this morning. I got a 30 day visa exemption for 960 baht, which includes the several km trip to the actual border and back. You need to find the small counter on the left as you arrive. I came with proof of funds, flight out and a hotel booking, although none were asked for. I would still recommend having these as back up if anything is questioned.
Quite a busy little crossing these days, so fairly safe to leave your transport parked up for the hour or so it takes. There’s even a nice aircon coffee shop and a few other shops in the vicinity.
TLDR : Answer Summary
The Ban Phu Nam Ron border crossing from Myanmar to Thailand allows travelers to obtain a 30-day visa exemption for the cost of 960 baht. This fee covers transportation across a few kilometers of no-man's land, as well as the immigration stamping process for both Thailand and Myanmar. It’s advisable to carry proof of funds, return flight tickets, and hotel bookings, even if they aren't routinely requested. The border has become busy and offers amenities like a coffee shop nearby. It is suggested that this crossing is more convenient and typically has fewer issues than others, like the Aranyaprathet/Poipet crossing.