Maracaibo
When buying a card, do I pay the victory points shown under the cost, and do combat-point costs get spent?
You pay only what is in the cost box (doubloons, plus any other symbols there). Victory points shown on the card are scored at the end, not paid. Everything in the cost box must be paid: a sword cost is combat points you spend from your ship board, not a mere requirement, and figures cannot be returned to pay it.