If interested in relatively-low-cost parking at your local airport, you might try Airport Parking Inc. Com:
You join for $10.00 fee to Miami agency and then book parking at hotels - Marriott included - near the airport. The fees are usually half that which you pay at traditional parking lots (on/off airport). You can then use the hotel shuttle bus for transport to/from airport. I used this recently for extended stay, parking at Marriott Atlanta Airport while gone.