Can I buy a car in Thailand with a DTV visa, and what documents do I need?

Yes you can. I just bought a car two days ago, you need certificate of residence, passport and visa. I Paid the full amount, no loan.

I bought a new car back in October with a loan from Navy Federal Credit Union. A Certificate of Residence (COR) is needed for registering the car in your name. The dealership offered to act as my agent to obtain the COR on my behalf but wanted something like 5k baht extra. I declined the service and got the COR myself at Chonburi Immigration.

Obtaining the COR requires a current TM.30 and copies of your passport and lease. We have a long term lease on a house here and I’d flown in and out since my last TM.30 report in August. In the past that seemed to be ok since I didn’t change addresses, but Chonburi now wants a fresh TM.30 after every re-entry regardless of address. I had already been in Thailand for a few weeks but didn’t have any issues getting the TM.30 done.

On a related note, a few months later in January they tried to fine my gf several thousand baht for a late TM.30 registration when she went to extend her tourist visa. She ended up using a border run service instead.

Yes, you can buy a car but you'll need to pay full right away.

taxes are huge you must be rich

Only thing you need is money

No documents per se to purchase the car but you’ll need a residence certificate from immigration to register it in your name.

You’ll probably need to provide copies of passport, entry stamp and visa as well, but I’m not 100% sure on those.