The East side of Cozumel is beautiful, but unless you rent a car...not many cruisers go over there.
IT is primitive...but has several COOL bars and porous rock where the surf shoots up through it.
The most economical private tour over there is
Cozumel Bar Hop.
http://www.cozumelbarhop.com/
It is $49 a person which includes 5 stops (3 on the East side and 2 on the West side) and you get a free shot at each stop.
It is a 5 hour tour and well worth the money!!