I am looking for a database of receipt images (like of receipts you get from the supermarket). I didn't found any open database, do any of you know something useful?
I would need a few thousand images at best, but less is still good.
You could try 'Neat Receipts'. It will do what you seem to be looking for. I have used it for a couple of years now because it is the only thing that I have found that will store scanned receipts and let me tag it with dates, amounts, taxes, vendor name and expense classification, without costing me a fortune. That being said, their support is painful and their software hangs often .. so it can be a bit of a frustrating experience.
Check out the ICDAR 2019 Robust Reading Challenge on Scanned Receipts OCR and Information Extraction: https://rrc.cvc.uab.es/?ch=13
You have to make a free account and then you can access the dataset, approximately 1000 images of scanned receipts.