It really depends on how many calls, emails and date internet you will use, as well as where you will be going and the other options available there. Haging out in Georgtown for the winter, offers very different communication options than gunk holing uninhabited islands for weeks.
In the Abacos for example, I can find WiFi at almost all the towns, but even in the southern Abacos, I've been anchored in many places with no Wifi Signal. However I get a cell phone
signal in all but a few cays.
Texting, last I was there was about 50 cents to send and a nickel or dime to receive, which can be an affordable option when all I need is basic communication. If a get a text, I can decide whether I need to get on the phone immediately or find wifi later, or just text a response.
One lesson I learned the hard way was to turn off all my data on my phone. Even email
headers and the data used just to check for new email can add up, so I learned to just turn it on to check a couple times a day. Having a new specific email account that doesn't get so much mail is another way to reduce data costs, just check your other accounts when you get wifi.
In the Abacos, there are a couple carriers that have service near many of the towns, but I often would go to a bar or coffee shop (hope town). Many had free wifi for customers. It's a good excuse to have a couple over priced beers and still spend no more than you would for a service, but again, this is only an option when you are at towns.
I did one year buy a Bahamas phone (not smart phone) and got pre-paid minutes. That's still fairly expensive, but cheaper than using a state side plan if you will be making a lot of calls.
One time I took an unlocked iPhone, bought the chip and a pre-paid card and could never get it to work. I think that's because at the time iPhones had to be hooked up to a real computer to initiate once receiving a new sim card, so that may no longer be an issue, but in my case, I spent a fair bit on a sim card and minutes which I could never use. (I should note, that getting it unlocked was just a simple call to AT&T)
The good thing is there are options, so you just need figure out what makes the most sense for your situation. When I first cruised the Bahamas, there was no cell phone service or public wifi. The only way to communicate was going to a phone booth.
Lastly, I found an iPad
very handy compared to a computer, as it was easier to take ashore and I could use it for many hours without a charge.