Where Bonaire is concerned, be mindful that round trip airfare doesn't vary whether you stay one week or three, and is basically averaged over the trip. The longer you stay, the less of a factor airfare is, since that cost is fixed but the cost of lodging, diving, vehicle rental & food rise as long as you stay.
A budget option on Bonaire is the Dive Hut. Pretty basic & not waterfront, but a way to save some money. For a few, costs me a few hundred more to stay at Buddy Dive Resort. But being on the water with a good house reef, I do a good number of night dives, and maybe an extra day dive or two, so I get more dives in that week. I like both. Depends on what I want which I pick. Remember that shore diving Bonaire you don't need to tip anybody. Boat diving pretty much anywhere in the Caribbean, you probably ought to tip. That adds up...
Here's a 2012 Dive Hut trip report.
Since Curacao and Bonaire are both possibilities, I recommend you do a Search with both those terms, and read the many threads debating their relative merits. Each is preferred by some, neither by all. And there are apparently some real differences. Let me share a 'Bonaire workflow' based out of Buddy Dive Resort.
1.) Arrive at airport, picked up & taken to resort, rent truck onsite, next morning do orientation & get $25 marine park tag. Buffet breakfast included.
2.) Get up when I feel like it, go load gear & tanks (EAN 32 nitrox at no extra charge) in the back up the pickup truck, head north. Hit 2 sites; maybe Andrea I & II?
3.) Go back to room, swap tanks , rinse off in the shower, eat simple lunch from grocery store (e.g.: fruit cocktail, PB&J sandwich, chips & soda) from Zhung Kong Supermarket (which is right up the road).
4.) Head south & hit 2 sites.
5.) Return to room, clean up, eat at Buddy's restaurant on site (since over 8 trips I've figured out most everywhere I go I get shrimp calamari appetizer & 'Catch of the Day' entree, anyway). Finish chewing while mulling over whether to do an evening/night dive on house reef. Don't feel like it. Consider when I get back home, I'll wish I had taken bigger advantage while on the trip. So I do it.
4 To 5 dives/day, no tipping, evening meal is expensive but the rest aren't, a tank of gas for the week will probably run around $80 maybe?
Of course, Bonaire could 'get old' after a couple of weeks straight.
As to the Florida Keys, I've heard repeatedly that the best diving is in the upper Keys. So I hit Key Largo -
my Sept. 2013 trip report. I found Rainbow Reef Dive Center's 10 trip, 20 dive package deal ($600 + tax & tips) about the cheapest boat diving I've ever done. Saying at the hotel beside it, I did 2 trips (4 dives)/day. 20 Dives in 5 days. Suh-weet! Airfare from Nashville much cheaper than Bonaire, flying to Ft. Lauderdale & driving to Key Largo. More topside entertainments (e.g.: zoos, Lion Country Safari, Jungle Island, and so forth) if you're willing to drive awhile.
Quick comparison:
1.) Bonaire has better viz. than Key Largo.
2.) Key Largo has more 'big stuff' besides tarpon.
3.) Bonaire is often lauded for being 'fishy.' 8 Trips to Bonaire, 1 to Key Largo, I think Key Largo was fishier...
4.) The glory of Bonaire is shore diving. The Keys are almost exclusively boat diving.
5.) Bonaire has interesting topography (e.g.: mountainous to the north, flat to the south, shrubby with a lot of thorny vegetation; there's a donkey sanctuary) topside.
6.) Key Largo connects to mainland U.S.A. so it has overwhelmingly more land-based attractions within, say, 2 hours drive.
7.) Over a period of a few weeks, I think a Bonaire trip will get cheaper than a Key Largo trip, since I'm guessing lodging + vehicle rental + diving + food cost less in total in Bonaire, & airfare is a fixed cost. But run your own numbers.
One more option, although I can hardly imagine being stuck on a boat (even a yacht) over 2 weeks - Blackbeard's Live-Aboard, at around a grand for a week (plus tips) with fairly cheap airfare to the Bahamas, sounds like as close to dirt cheap good conditions ocean diving as you're going to get. Be mindful the Bahamas' water gets cold in the winter time.
Richard.
P.S.: Someone made a good point about per diver vs per unit pricing. The Courtyard Marriott was fine for me because I had 2 non-diving adults & a baby daughter in the room with me. Traveling alone vs. with at least one roommate has a big impact on cost.
