What are cost-effective alternatives for a 5-month stay in Thailand considering the high visa fees?

That's similar to a visa here in Myanmar

Looks expensice but it is still a good price when you consider how much time and money you'll spend to get other visas multiple times to make the 6mth period. Sure new guverment in NZ can do smth about it if we ring the bells to local MPs. Same with Vietnam and other asian countries.

Go in on a 2 month visa, or 2 + 1 month and visit VN for a month or two in between.

Unfortunately there is no other place for kiwiz to get a 6 month METV ex😕pt the thai consulate in Wellington (that did just do a CRAZY price incr😕se :O) I mean even a single entry tourist visa from that consulate is NZ 300 😕 )

Your best bet is to fly in free stamp (30 day visa exempt entry), take the 30 day extension on that at the immigration office where you stay for 1900 baht.

THEN

either bounce out and back by land to get a NEW free stamp (30 day visa exempt entry) which you can do TWO times a calendar year (Jan 1 - Dec 31) and take the 30 day extension on that

OR

Go to a thai consulate in a nearby country that borders thailand, get a single entry tourist visa, enter thailand by land, get stamped in for 60 days and take the 30 day extension on that

Your question 𝗪𝗵𝗮𝘁 𝗮𝗿𝗲 𝗼𝘁𝗵𝗲𝗿𝘀 𝗽𝗮𝘆𝗶𝗻𝗴 𝗳𝗼𝗿 𝗮 𝟲𝗺𝗼𝗻𝘁𝗵 𝗺𝘂𝗹𝘁𝗶 𝗲𝗻𝘁𝗿𝘆 doesn't even factor into it because you have to get the 6 month METV at the consulate in your home country