Edit Ticket Price
Once you've created a ticket price, you can edit the price at any time by going to Pricing -> Ticket Prices next to your event.
Once a ticket has been sold at a set price, the dollar amount of the price can no longer be edited (other options such as name, description, and other settings can be edited). Editing the price's dollar amount can also be disabled if you have a ticket sitting in your cart for that price, so if you're testing things and now want to edit the price, remove the ticket from your cart or wait for your cart to timeout.
If you need to change the dollar amount of a ticket price after it has already been sold, here are the steps:
Delete the ticket price — deleting a ticket price will not affect reports or existing orders and can always be recovered at any time.
Click + Ticket Price and create a new ticket price at the new pricing level
Essentially, delete the old price and replace it with a new price.