How can I hide the prices from the widget?

In the price options and fields settings, set the price to 0. This will hide the prices from the invoice items.

To hide Total and Deposit, open the widget settings and go to the Design panel. Check the Custom CSS style option and add the following CSS:

.order-totals { display:none; }
.reservation-invoice__total-label { display:none; }
.reservation-invoice__total-amount { display:none; }

As a result, all prices will be hidden on the reservation and cart screens: