Allround Automations occasionally offers free community licenses for PL/SQL Developer. These licenses are usually limited and require you to meet specific eligibility criteria.
If you are looking for a free, permanent IDE for Oracle development, consider these alternatives: Oracle SQL Developer: This is a completely free, no-cost product provided directly by Oracle. utPLSQL Developer: open-source option for unit testing within PL/SQL. Important Security Note: pl sql developer 14 license key free link
If your trial has expired and you cannot purchase a license, there are excellent, industry-standard tools available for : permanent IDE for Oracle development