What you'll need
Four accounts. Free or close to it.
n8n
Free self-hosted, or n8n Cloud starting $20/mo
Google Calendar OAuth
Free with any Google Workspace or personal account
OpenAI API key
Pay-as-you-go, only billed when conflicts exist
Slack OAuth
Free workspace tier works fine
The math
What this is worth, conservatively
Prevented conflicts per week (busy team)
1 to 2
Average cost of a missed appointment (sales call, showing, partner review)
$300
Recovered per week
$300 to $600
Annualized
~$15,000 to $31,000
Cost to run this template forever
~$12/year
Numbers based on internal observations of mid-size teams running multiple booking tools against one calendar. Your dollar value per conflict varies with revenue model and meeting type.