What you'll need
Three accounts. Free or close to it.
n8n
Free self-hosted, or n8n Cloud starting $20/mo
OpenAI API key
Pay-as-you-go, ~$0.0001 per message
Twilio
$1/mo for a number, ~$0.008 per SMS in US
Your booking software
Webhook on appointment-completed event
The math
What this is worth, conservatively
Review volume lift vs no automation (BrightLocal)
4 to 7x
Business with 100 appointments/month, 5% reply rate without prompting
5 reviews/mo
Same business, with this template (~25% reply rate)
25 reviews/mo
Cost to run this template forever
~$36/year
Numbers based on BrightLocal's review-volume benchmarks for businesses that ask vs ones that don't. Reply rate varies by category, ticket size, and how recently the customer has been served.