We occasionally get a request from someone who wants to get a little bit of money up front and then take the remaining payment on the day of the event.
Well, if you're one of those people, you're in luck! Using the Shopify Point of Sale app it's possible.
Here are the steps written out for you.
Create an Experience for the amount of the deposit you want. e.g. "I want people to pay $20 per attendee and then $80 more when they arrive for a $100 total."
In this case, you'd create a $20 Experience.
Prominently note somewhere in the title, sub title, and/or main copy content area that this is only the deposit and that you'll owe more when you check in.
Duplicate that Experience using the Actions > Create Duplicate feature when you're looking at the list of your Experiences in the Shopify admin. Edit that duplicate Experience to cover the remaining cost. e.g. If you charged $20 for the deposit of the $100 total cost, you'd then make this duplicate Experience $80
You can choose to hide the $80 duplicated Experience in your online store so people don't sign up for it there. There are a few ways to do this but the easiest way is to simply remove it from the Online channel. In the Shopify admin, just go to Products > Your Duplicated Experience > Sales Channels > Manage > Uncheck "Online Store". (Info about sales channels in Shopify)
When your customers arrive on the day of the event, you can check them in and then charge them for the remaining amount by choosing the duplicate Experience you created.
At this point they would have paid the $20 deposit and also made their final $80 payment.