There are only six options; the four best are reviewed here. If you are on a budget, you may want to look at the 1970s government-built Mafia Island Lodge (www.mafialodge.com), but I suspect you'll find much better value for your money on Zanzibar. Located on Utende Beach (a 10-min. walk from Pole Pole and Kinasi), it was the first to open on Mafia, and although the airy double-volume public lounge/bar has stood the test of time and remains a great space, the same is not true of the rooms. It's also set too far back from the beach, regardless of the tide -- by the time you've reached the lodge, you are perspiring and ready to turn around and head back to the water (admittedly, there is a beach bar to quench your thirst while there). Despite the fact that it is quite a bit cheaper than the other options (126€-150€ double standard room, full board) I don't think these rates fully reflect its inferior position.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.