Joanie, in Ft. Lauderdaly you can go to the north end of the strip (Sunrise Blvd) and park for free. I hit it once in a while, but I like the south end better around Las Olas Blvd. Lots of parking if you get there early, you'll definitly see all the parking lots. I've found a lot of gold and silver in those areas.
In Hollywood you can park 1 block south of Johnson St. right on the beach. Used to be real good there until they pumped new sand in about a couple yrs ago. Still good if gets crowded.
My favorite hunting area is definitly South Beach. If you go really early you can get parking on Deco Drive between 5th and 15th St. Miami is good hunting from 5th Street to the 80's. Further north Haulover is good with more than enough parking.
Hope this helps!
HH 8) surfrat