The cost for the week depends on the yacht you choose. The price of the yacht is fixed and you divide this between however many people in your crew. All available yachts with prices are viewable here.

See our additional costs guide 
here for a price estimate of fuel and port fees.

With regards to eating and drinking out, it can depend on the person, so we advise you to expect to spend what you would on any other holiday. You can make it cheaper if you choose to eat meals on the yacht, for which you can buy food and drink at the supermarket on arrival.

For cabin bookings, this is slightly different, as some meals are included. Please see 
here for full details of what's included.