We took a taxi right from the port. They will ask you where you want to go. We said Atlantis and there were three others that wanted to go. It was $5 each and someone had to pay the $2 bridge fee (just one $2). She dropped us off at the bottom of the hill and we had to walk up to the entrance. Going back she said we would have to walk down the hill (as the driver told us). We did and the taxi driver that picked us up said we could have gotten a taxi from the entrance to the Atlantis and saved us the walk down the hill. The hill is not that bad. Again, you may need more than 2 people for the $5.
We also went to Baha Mar another time and took the jitney from town for $1.50 pp each way. Jitney drops you off by the resort at the street but there is a long, up hill walk to the resort. Baha Mar was really empty. We prefer Atlantis for the casino.