If you go to the london casino and bet like other tips suggest (big bets and save and load technique) you can transfer the chips into TB by buying the endless supply of ''recovery powder'' and ''god's ambrosia'' and selling them at the nearby shop. You can only hold 9 of each at a time so you have to run back and forth to (each time you will get roughly 27,000 TB). Then you visit shops that offer ''skill gems''. Buy the ''skill gems'', go to the menu and go to the ''use item'' menu (to convert them into ''sp'' points) and apply them to the desired characters in your party (again you will only have the chance to hold 9 at a time).
The conversion of casino chips to TB (through buying and selling the two infinite items is somewhere around 16TB/casino chip.