It really depends on you as a person. Are you planning on gambling? Are you planning on shopping? How about drinking? Playing bingo? Going to David's? Are you prepaying for excursions and your gratuities?
My husband and I spent about $400 for the week last year with a little shopping, a trip to David's, some drinks.
I know my parents are planning on bringing about $1000 with them this year. I keep telling them that's too much (only because I know their spending habits), but they are playing the "rather be safe than sorry" card. Not knowing your spending habits, it's hard to tell you how much to bring.
Random third-party websites are no substitute for personal experience.
Pirates: Putting the Fun in Funville since 2011