I went from Thailand to Laos over land (Ubon Ratchathani- Pakse) and it was with 1 bus. So you get off the bus in Thailand, walk to immigration Thailand, get an exit stamp, walk to Laos, fill in paperwork, pay 30-35 dollars (or Kip or Baht), get visa in Laos, get on the bus again (bus crosses border without passengers). This was in my case, but it can be different! Not all checkpoints allow VOA in Laos I've heard
Good to know. Where can I get the ED visa when I'm already in Thailand? Like an immigration office in Bangkok for example? (How does that work, how long et cetera?) Do you mean a proof of 20k bath or do I have to pay that?