Where a default price is set for a client
When viewing the client details, you will see which price book is set for the client under their settings:
Change a client's default price book
To change the client's default price book, click on the EDIT link in the top-right-hand corner of the Settings box (under the client's details).
Once you click edit you are able to select the new default price book for that client.
Remember to click on the update button to save the change.
Changing the price book for a shift to not use the client's default price book
When viewing the shift you would like to change the price book for click either the Edit Shift button or Edit Program button (to edit more than one shift).
Next click on the Add Clients button:
Next chose the appropriate price book for that shift.
Remember to click on the Done button at the bottom of the page.