$140 /night with dives is pretty tight, yes. Dives are approximately $40-45 each. You can likely negotiate a slightly better price per dive based on a block of dives.
Therefore, I'm thinking if that's your price range you should look into staying at a hostel and you could probably get a private room for $50-60 and that will get you into your budget tho' only 2 dives a day. Of course, if you're willing to go full hostel in the shared rooms, you'll be able to do much better. Both Hostel la Vista and Sandbar are well located and are reviewed highly. I can only speak for their locations as I'm not a hosteler. The location of either is excellent.
(I do not recommend Pedro's )
Therefore, I'm thinking if that's your price range you should look into staying at a hostel and you could probably get a private room for $50-60 and that will get you into your budget tho' only 2 dives a day. Of course, if you're willing to go full hostel in the shared rooms, you'll be able to do much better. Both Hostel la Vista and Sandbar are well located and are reviewed highly. I can only speak for their locations as I'm not a hosteler. The location of either is excellent.
(I do not recommend Pedro's )