What is fair CAM cost per sq ft in a 100,000 sq foot plaza with 25 units, located in Jupiter Fl.

Its not a matter of fair, its a matter of dollar sense. You have some basic math to do. Add up all your costs to maintain the common area (lanscaoing, snow removal, etc.) divide it by the total space then charge each space as much as they use.

depends on location,condiition of property,desireability,aprasial,recent sales in the
same area and the financing available. Check it out ,also check out the kinds of
insurance required and the property tax.
P.S. There is no snow in Florida.

pro-rata share: Take total actual CAM expenses from the prior year (or CAM budget if you know that planned expenses are different that the prior year) and divide by 100,000 to determine CAM cost per square foot.

There is no real "fair" - only what you actually pay for expenses. I would recommend going over your expenses for last year (and what expenses you've had for this year thus far), anticipate a slight increase for the coming year and you have your CAM expenses.
Now, the CAM expenses are only one "N" of what is known as "Triple Net" (NNN); with NNN leases, there is also property taxes and insurance. However, in this market, and in the Jupiter/Tequesta area, many landlords are doing "Gross" leases and are paying their own CAM, insurance, and taxes.
Hope this helps.

The answers generated by others are fair and reasonable. But do not take into consideration neccessrily that you property or the property in question may or may not be more or less efficient than others in the market place and therefore the cam charges could be higher or lower depending on those conditions.
The fact is the lease document(s) in question that the property is subject to will control what can be charged as a CAM charge and the actual calculation of the charges is a fairly simple mathematical process.
Some leases however will allow rounding up, some allow for adiminstration fees to be charged on top of the actual hard or direct cost.
The net net will alwys come the the end fact that your property must be ultimately rented for MARKET rent and that includes both CAM charges and base rent.
There are numerous ways to positively effect your CAM charges and reduce operating costs that require effective management techniques and expertise.
Not a real direct answer in some ways I realize but since there are so many variables there is no direct and easy answer with out lots more data.