@Brittany *******
I see now. We just pay 53 NZD for single entry tourist visa in Norway. Then a cheap onward ticket bought online is far cheaper.
This is from the embassy in Norway, it’s equal in London, but there’s no official statement regarding this. It’s several ways to “leave” Thailand and I know people are allowed check in just with a bus ticket bought online from Nong Khai to Vientiane. I know someone also was allowed check in Malaysia with a bus ticket after some discussion.
As said this is rarely checked at the immigration, but the airlines can be fined and responsible for your return if formal requirements are not fulfilled. So I advise you to call your airline and ask directly. If you feel unsure a cheap flight ticket out could be a cheap insurance.