Overstaying the Stay Authorization
The fine for overstaying a stay authorization or its extension is $230 (in 2024). You only need to pay this fine if you plan to return to Ecuador within one year. Because paying this fine is only possible at a bank in Ecuador, you can ask a migration officer at a migration office to issue the fine prior to leaving Ecuador. The migration officer will then give you a payment instruction.
Be aware that you also have to pay this fine when you apply for the extension on day 90 of the stay authorization.