I bought a cheap Coral phone from Digicel on my 2nd trip - back then was about $25. I like having the same Jamaican ph# every trip so work/friends/family at home can reach me in emergency. Plus all my saved Jamaican contacts are stored away, I don't have to re-enter them all in a loaner phone.
I shopped at Digicel store on last trip for phone for GF and cheapest phones were closer to $40 than $25, but that is route I would go if you just want your own cheap phone in Jamaica - rather than buying in US. You still have to make a stop at Digicel store. And you run the risk a cheap phone won't work on their network - I brought a few down last trip for gifts, and even though were unlocked GSM, Digicel said they couldn't work on their network. If you want a full-feature modern phone, like a Blackberry or Android - those are VERY expensive in Jamaica and I would follow other's advice and buy an unlocked phone on online discount or auction site.
I've just used OnLine Topup on digicel's website to add minimum topup (under $5) on first of every other month - my phone has worked soon as I got off the plane every trip without doing anything extra. Not sure why other's are not able.
