US currency can be used at the rate of two Barbados dollars for one US dollar. There are plenty of ATM machines all over the island (including in the departure area of the airport) that have access to the major banks in North America. All major US and Canadian bank cards work fine.
Bring mosquito repellant. There are (infrequent) outbreaks of dengue fever, (more recently) chikungunya, and (most recently) zika, so check ahead of time. In the recent past, none of these has been a problem for workshop participants. Zika infections are usually mild, but are linked to birth defects (microcephalitis). Anyone who is pregnant, may become pregnant within six months, or may impregnate someone within six months should be aware of the risks.
For up-to-date information about security and health in Barbados, consult the Government of Canada Barbados Travel Advisories.
There are computers on campus with access to the internet. Bellairs is fully covered by a wireless network called Bellairs or Bellair's. The SSID and password for this network will be provided to participants in a welcome email.
Food is not included in the room rates.
Finally, this (older) PDF document contains a description of the house rules of the Institute.