External Black-Box Penetration Test

I need an external, black-box penetration test carried out against three separate /24 IPv4 ranges that power our public-facing web applications, email servers, and SIP services. The exercise must satisfy... (Budget: €30 - €250 EUR, Jobs: Compliance Auditing, Computer Security, Internet Security, Linux, Network Security, Penetration Testing, Security Auditing, Testing / QA)