Originally Posted by
tide
Another place to get change is from the highway tolls. Most of us here are familiar with this but for those new to Bangkok, you hand your taxi driver cash when approaching toll booths, of which there are 2 on a typical journey to the city center. Taxi driver then hands cash to tollbooth operator, and the change makes its way back to you. They will take big bills with no issue
That's how I usually break 1000 baht bills.
There is risk, albeit slight, that the driver will have fastpass and no money will change hands in which case that's not an option. I'll second
Plato90s recommendation to patronize 7-11 or Family Mart prior to departure if you need change.
Worst case scenario you can always get 'small money' at the hotel upon arrival.