Build custom voice assistants and AI phone systems for businesses using tools like OpenAI Whisper, ElevenLabs, and telephony APIs. Create intelligent phone systems that can answer calls, book appointments, qualify leads, provide customer support, and transfer calls when needed. Voice assistants can work 24/7 and handle multiple calls simultaneously. Charge $3000-8000 for initial setup plus $800-2500/month for hosting and management. Target restaurants for reservation booking, medical practices for appointment scheduling, service businesses for lead qualification, and customer service departments for after-hours support. Income potential: $12000-35000/month with 8-12 clients. Tools: OpenAI Whisper, ElevenLabs voice cloning, Twilio, VoiceFlow, cloud hosting. Difficulty: Advanced - requires understanding of voice AI and telephony systems. Setup cost: $300-800/month for APIs and hosting. Time: 20-35 hours per project, minimal ongoing maintenance.