about 100 to 200 dollars
you dont have to take a taxi
you could use transit instead
you would first take Santa Monica #10 into los angeles riight to union station
then you take metrolink direct to san bernadino and then if you need you can then use the local
Call a taxi company, its not that hard.
The fare will be approximately $240 PLUS tip.
Travel Master is correct about the best way to get there by public transit.