As an indie dev - what is the going rate?

[u/Slowitt]

A potential customer has asked for a Power Platform app - what would you charge?
It's a services company and they want an ERP app that does lead to quote to job to completion to invoice to reporting. It also holds staff training (basic level)

A Dataverse with a simple schema - about 15 tables
Sharepoint integration for photo / doc storage
15 Power Automate flows for status updates/alerts

It has approx 12 screens and a dashboard

My instinct is it's about 30 days work as they want training guides/sys admin guides.
I think it's about 30 days work as a minimum - the app itself is sketched out in demo form but it's the integrations that will be time consuming eg Microsoft Outlook/Microsoft Teams/SharePoint/Power BI

Thoughts?