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, ~$0.0002 per message
SMTP or transactional email
Gmail, Postmark, SendGrid, Resend — your call
Your booking or order system
API access or webhook from Mindbody, Vagaro, Toast, Shopify
The math
What this is worth, conservatively
Repeat-customer lift from automated post-service check-ins
8 to 12%
Business with 200 completed jobs/month, $80 average ticket
$1,280 to $1,920/mo recovered
Annualized
~$15,000 to $23,000
Cost to run this template forever
~$24/year
Numbers based on industry benchmarks for repeat-purchase lift after personalized post-service outreach. Your actual results vary with category, ticket size, and message quality.