is it llegal to overcharge for an item in FL. I recently had an air cinditioner motor installed. paid 1900.00 - actual cost is 285.00

Typically no, it is up to the consumer to investigate wheher they are getting a "good deal" prior to making it. The exception to this is if the transaction is waaaaaaayyyy out of line or if the consumer is in a protected vulnerable class like the elderly. Byexample, 70 y/o lady hires AC contractor for yearly maintenance, who then tells her that her motor isnt working right (when it is) could start a fire if not replaced immediately or require much larger repair (scare tactic)and then charges $1,900.00 for a motor that most other A/C people would charge a customer  $285.00 for. This fact pattern would likely be an unfair or deceptive practice. In contrast, a customer charged $1,900.00 motor, that he later finds on internet for $285.00 cost, is more problematic, as consumer is not entitled to get products at cost from AC repair people any more than other businesses, like grocery stores,auto repair places, hospitals etc.