As an intern you have the option to eat breakfast and lunch at the dive center, or the hotel on working days. Therefore, you only have to think about buying food or groceries in the evenings or you days off. Depending on you, you should plan in between 30 and 100 Euros per week regarding food.
The housing itself also depends on you. If you decide to live in the hostel La Tortuga nearby, you should plan in up to 500€ per month for accommodation. Depending on your lifestyle and expectations you can find apartments for more or less money as well.
For all courses (excluding Dive Master) you will have to pay a 95€ PADI fee. This fee goes directly to PADI and will cover the costs of your e-learning and Certification. The rest of the money will be for to the dive center to cover your course fees, however, you as an intern will get a 25% discount of that money.
Prices for you as an intern:
Open Water Course: 316,25€
Advanced Open Water Course: 271,25€
Deep Specialty (40 Meters): 166,25€
Nitrox Specialty: 166,25€
For the Dive Master Course, the PADI fee is a bit more expensive. It includes a crew package for 180€ and next that 100€ for your application form that will last one year.
Dive Master: 562,50€ + 280€ PADI FEE = 842,50€