Originally Posted by
transpac
I think the published DLT flat-fare from many locations in Bangkok to Pattaya is 1,500 baht. You can use Grab Taxi but you'll have to negotiate the fare with the driver directly. Once you make your request the driver will call you to discuss, and decide on a mutually acceptable fare. I think there may be some tolls, and the 25 baht Grab Taxi surcharge.
The more passengers you have in your party the more a cab or private car service makes economic sense.
There is another consideration that I wanted to mention: there are plenty of aggressive drivers in Thailand that is for sure

it could be your driver or the other drivers on the road. I have read horror stories of metered taxi drivers going over 130km/h between cities and the passengers feeling like they risked life and limb in the process. Having often experienced such driving between BKK and downtown is enough of a cheap thrill

I can't imagine it for over an hour.
So for safety reasons I prefer being on a large bus on the highway portion of the trip, and going with a professional organization that has the resources to recover you decently if there are any issues. As always YMMV.
SunLover