ParknFly has now opened at FLL and it seems to be the best service of this type that I have ever seen. It is in a really easy to access location at the end of I-595 and I now have used it twice, both times returning about midnight, and both times a van was around to pick me up within five minutes of my arrival. Also, each time a van was at my car to take me over before I finished getting my bag out of the trunk.
There are free day coupons around on the web and the usual AAA and senior discounts are available.