You may be better off using Target or Wal-Mart Gift Cards. You can put any denomination on them ($5, $10, etc.) and the crew "Fun Bus" definitely goes to Target when in port (we witnessed these two times now for 7-day sailings). We saw lots of crew carrying Target (and Winn Dixie) bags back to the ship after getting off of the bus.
Our servers (both from the Philippines our last trip) told us the crew routinely uses the internet to communicate with their families, including WebPhone and other services.