Does anyone know of somewhere in the Jacksonville Florida area where I can pitch a tent for the weekend?

Hidden River nudist park is not that far from Jacksonville, FL.  http://www.hiddenriverresort.com/

There is a ground fee of $20.00. So for a nonmember the cost would be $45.00 per night. Seems to me they want to discourage people from going there. Most campgrounds charge a lot less.

A room at a motel is way more than $45. From their website:
http://hiddenriverresort.com/activities.html#rates
             Hidden River Members    AANR or Associate Members    Non Members
Grounds Fees    No grounds fees except for for special events.    $20    $25
**Tent Camp Site    $15    $15    $20
**RV or Trailers    $20    $20
+ Grounds Fees    $25
+ Grounds Fees

Their fees are in line with most parks of their ilk.    The management is wonderful, the grounds relaxing, members friendly.