Hi,

For Odoo 15 Community, here are the realistic options:

Pay-per-scan (most common model):

• Klippa and Invoice Ninja integrations; per-document pricing, good accuracy
• Nanonets; has an Odoo connector, per-page pricing but good ML accuracy

Flat/subscription-based:

• invoice_ocr by some OCA-adjacent vendors; search the app store for "OCR invoice" filtered to v15, some offer monthly flat pricing
• Mindee; has an Odoo module and offers a free tier (25 pages/month) plus flat monthly plans, which fits your preference

Self-hosted / free (no per-scan cost):

• Tesseract + custom module; free but requires development effort and accuracy is lower than cloud OCR
• account_invoice_import from OCA; handles structured formats (UBL, ZUGFeRD) without OCR, free if your suppliers send XML-based invoices

Recommendation: If you want flat pricing with good accuracy, Mindee is currently the best balance for Community. If your suppliers can send PDF/XML structured invoices, OCA's EDI modules eliminate OCR entirely.