A map of Barbados is hard to call complex, as the island itself is not very big at all, 23 km wide and 34 - long. However, if you prefer to travel without a guide, you will need to understand the location of the main attractions of the island. Barbados is also well served by buses, and a map of the country will help you understand the routes and time it may take to get to the botanical gardens or caves.
It is hardly possible to find a map of Barbados on the spot, so you should buy it in advance. Wi-Fi in Barbados is available only in the cities, moreover, it is paid, so you should either download a map in advance or print it out. However, there is no point in worrying about your equipment suddenly running out of power, because it will be easy to get to your hotel from anywhere on the island. So there's little point in loading yourself up with extra paper.
tripmydream has prepared for you a detailed map of Barbados, which will certainly come in handy when traveling.