In order to create an offer with a deposit and provide to your customers the possibility to pay the remaining amount on spot, all you have to do is in Step 3 of the offer creation to create two "Ticket Category" on the creation of your offer, one with "Deposit" and one with "Total Price" as shown in the pictures below.
The "Total Price" should not be visible but has to be selected as the main price in order to make customer see what is the total amount to be paid on spot.
After all these steps are reproduced, you will have the following result on your ticket shop.
After all these steps are reproduced, you will have the following result on your ticket shop.