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.
I know the Fort Myers Hotels | Courtyard Fort Myers at I-75 and Gulf Coast has parking available for RSW during certain times of the year, not sure about high season. I believe you arrange it through the hotel and they shuttle you to the airport.
fschumpert, on a similar note, sometimes airport Marriotts will have a parking included rate. I remember the EWR Marriott sometimes runs that deal. The room rate will be maybe $10 more but you can park your car for up to 4 days. So instead of paying like $32 a day in the EWR airport daily lot, stay at the EWR Marriott one night, fly out the next day and leave your car there for like $10 extra. In my example, you save $120. Of course you have to pay for the night so if the room is expensive it may not be worth it. But if you are taking a 6AM flight, its alot easier to get up at 4AM, catch the shuttle to the terminal and be all set rather than getting up even earlier and driving and parking and all that.