Can anyone advise if there are any visas available that allow purchase of a car, outright or in instalments?
Currently on non immigrant O spouse visa.
TLDR : Answer Summary
Yes, you can buy a car in Thailand with a non-immigrant O spouse visa. While a work permit is not necessary, foreign car loans typically require a Thai co-signer or a substantial deposit, along with proof of income. If paying in cash, obtaining a Certificate of Residence from immigration is recommended.