A simple Udemy-based project. This application somewhat repeats logic of service called Stubhub. Users can list their ticket for some event (concert, sport) for sale, other users can purchase this ticket. Any user can list tickets for sale and purchase tickets (even their own... if they wanted to...).
When a user attempts to purchase a ticket, the ticket is "locked" for some amount of time. The user should enter their payment info before the time is up. While the ticket is locked, no other user can purchase the ticket, it's not even going to display to other users. After the time expires the ticket should "unlock" automatically.
Ticket prices can be edited if they are not locked.