Comprehensive Web App QA Testing

We are launching a new web application. It is to help hosts manage events. It is a small application (first release) with a form for host to create, share the link, allowing guests to respond. Also there are email notifications... (Budget: $2 - $8 AUD, Jobs: .NET, API, API Testing, Internet Security, Penetration Testing, Security Auditing, Software Testing, SQL, Testing / QA, Web Security)