Overnight Anchorage Miami, FL

[cfoxcvg]

Hello, I am looking for a safe and preferable cheap/free place to anchor my boat for 1-3 nights. We are off to Bimini but I am taking the boat down to Miami first then driving down once the little lady is off work. A place to park the car for a few days and close dinghy access would be great, also late night access is almost a must as we would like to hit the MIA night life before we head out.
Appreciate any info you can offer.