deckhook

Yes we are and so glad to find someone else going on this cruise.  We are a family of 5 heading there and so excited.

Anyone going 27th May 2019, 5 day Key West, Cuba, Cozumel...

It depends on if you are looking at a box of 10 or a box of 20 (Some brands do not sell boxes of 10 though).
I bought a box of 10 Hoyo de Monterrey (Epicure Especial) in Grand Cayman this summer at it was roughly $150, so $15 per cigar, individually they were like $16.50 each, multiply that out and you would be around $300 for a box of 20, they probably come off of that a little.
Since the cigar will not have to be exported from Cuba and imported to another island I would expect to pay less in Havana, IMO.

@tiny260   John I don't know a thing about you personally but your affinity for cigars is all I need to know man.    Hopefully one day in the future we can ponder the meaning of cruise life over a couple of cigars and spirit while at sea!

Yes
and yes, this has turned in to my go to Cuban.
For the OP, @deckhook , I have not actually been to Cuba but buy a lot of the cigars at surrounding islands, the only caution I was given for buying Cuban cigars was to buy them from an actual store, possibly one close to the cruise terminal, DO NOT buy them from anyone selling them on the street, I was told these cigars could have anything in them that looks like tobacco, but it would not be tobacco..

https://www.tripadvisor.com/Restaurant_Review-g150809-d2172821-Reviews-La_Casa_Del_Habano-Cozumel_Yucatan_Peninsula.html
Out of your 3 stops this is the only "Official" Cuban cigar distributor on Cozumel, you will have to leave the port and go downtown to get here, but don't buy any "Cubans" from anyone or any place else, I'm not even sure that the humidor on the bottom floor is legit, but I know the one on the top floor is.
When the waiters and people on the bottom floor ask you in for lunch, just tell them you want to visit the humidor on the second floor (Which is also part of the restaurant, BTW), don't expect them to give you recommendations, you will have to know what you want, they can point out a specific brand, but that is about it.
If you or your husband researches, La Casa Del Habano is one, if not the only authorized Cuban cigar distributor for the whole Caribbean. It is the only store I will visit to buy my Cubans if at all possible. I did find a really good store on this last cruise in Grand Cayman, awesome selection and service, very knowledgeable staff.
There is also a La Casa Del Habano in the Falmouth Jamaica port shops now if anyone is interested.
BTW, everything @Todd W says above I'll add a "Ditto"...

I was just at terminal A and even though I didn't park there but parked at Best Cruise parking.
It is a covered parking garage where there are a lot of Sheriff patrol cars parked there. it was safe and secure and cheap $80 for the week, however the transport to and from the terminal was terrible.
They say they have a shuttle running every 15 min but it is more like 1 hr. My wife had a fit at how they ran the operation there.
I would use them again but I am cheap. I can't use them again as I can't afford a divorce.

I never even look at any options other then at the terminal.  I don't see the savings outwieghing the convenience, especially at the terminals with the parking garage attached like Canaveral and Miami! 

I was just at terminal A and even though I didn't park (Uber) it is my understanding that there are porters waiting in the parking garage and a conveyor belt system that runs to the terminal so you don't have to lug all your stuff all the way over to the terminal and then drop it off.

I don't recommend parking off site in Miami. I've heard a number of stories about incidents at off site parking.
As @Brobbins246 said, the convenience of parking at the port is hard to beat.

If you're sailing out of the new Terminal A in Miami, there's a parking garage right at the curb there.  A little pricey but you can't beat the convenience.