About 2 to 3 times a year, I will "hop" down to Fort Lauderdale from So Cal, for an extended weekend of some warm water diving & relaxation from the Los Angeles Rat Race. I usually get a cheap rental car by the airport and grab a cheap motel room on the beach ( A1A) and dive with Amercian Dream or Sea XP. Used to go with Pro Dive but they are out of business. Here are some recommendations for all the above;
Sea Club Resort - $60 a night, coffee shop, bar, pool, cheap, decent, on the water, not fancy.
Bahia Days Inn - On the water, restaurant, close to dive op's and close to the Elbo Room and other great little restaurants on the beach right there.
Sunshine Rent a Car - $12 a day, close to airport. Nice guys, no "insurance" hard sell, decent cars. Having a car is good for the trip to CVS or Starbucks or Reef Photo or Las Olas or out to Divers Direct/Pro Bass or Down to Aventura Mall, or perhaps even hop down to Key Largo.
There are quite a few other hotel/motel options around and on the beach that are reasonable. Do a little homework and you will find. I ALWAYS have a great time there.