Buying a car in thailand

I don't know why people feel they need a car in Bangkok but if you must have one you will need certificate of residence from immigration or your embassy.  If you have a work permit I think that will also work instead of previous mentioned but not sure.  You will also need copies of passport info page and visa.

If you buy new dealer will handle registration.

If buying used you will need to take care of registration yourself.  Do not purchase used car from person that is not listed as owner in blue book and never purchase used vehicle that does not have blue book.  It is also best for seller and buyer to complete transaction at Department of Land Transport office. The DLT will insure serial numbers on engine and frame match the blue book so do not pay before everything is verified.

Hi and welcome to the forum thereisnospoon!

Maybe you should have a look at the Buy & sell section of Thailand classifieds.
It might help!

Regards
Armand

Thai driving license, Work permit or house registration, non immigrant visa, financing a car for foreigners in Thailand is not easy unless you've been living here for a while and have a good credit, also they look at the basic salary and in most cases would prefer if its over 100,000 Baht, if your buying a car at full value with cash, you shouldn't have to many problems, just walk into any dealership and they will guide you through the process and in most cases take care of the paper work for you. As for 2nd hand cars straydog explained it spot on