I work also in the HORECA (this means Hotel-Restaurant-Café),
as a waitress in the hotel restaurant.
Fifty (50) Euro is the amount of money that you will earn here in Holland per day, not per hour.
You will work then 8 hours per day, 5 days per week (average).
At the hotel where I work, the rate starts at 9 Euro per hour, if a person older than 20 years.
I hope this piece of information if of any help to you.
Good luck!
Santana.