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 e-commerce or CRM
API filter for last_order_date or last_visit_date older than 90 days
The math
What this is worth, conservatively
Reactivation rate on a 90-day-inactive list
5 to 10%
Business with 5,000 customers, 30% inactive at any time
~1,500 inactive contacts
Reactivated customers per quarter (7.5% on the segment)
~110 customers
Cost to run this template forever
~$12/year
Numbers based on industry benchmarks for win-back email open and reactivation rates. Your actual lift varies with category, average order value, and how recently the customer was active.