To change the currency symbol that MainBoss Basic uses, login as ADMINISTRATOR and go to Administration -> Preferences -> Other. Type the desired currency symbol (or string of symbols) in the "Currency Symbol" field.
If your keyboard doesn't have the symbol you want, you can specify the symbol by typing a special keyboard sequence. To do this, first turn on NUMLOCK by using the NUMLOCK key (if NUMLOCK isn't already on). Then hold down the ALT key and type an appropriate series of digits on the keyboard's number pad. The list below shows the keyboard sequences required for a few commonly used currency symbols.