That would depend on how you got the turtle. If from a pet store or other individuals selling wild caught adult, it might cost about $40-$80 US depending on subspecies. Captive bred go for more - I've seen someone trying to sell CB ornates for as much as $250. I hope you know that they aren't like aquatic turtles. They must have a balanced diet of vegetables and insects, require a lot of space, and preferably be kept in an outdoor enclosure when possible (warm months). Prone to respiratory infections when you make the slightest mistake on temperature and humidity.
I got my two when they were very small several years ago. They are captive bred and I think I paid $75. Not saying you will find a deal like that but thought I would put it out there. Whatever you do make sure you get a captive bred animal. Box turtles are in enough trouble without people taking them from the wild to make as pets. Captive bred also adapt much easier to being pets.
Mo mine was given to me by a friend who no longer wanted to care for it the only one ive seen for sale from a petstore was 80$ for a wild caught ornate. Getting them straight from the breeder/collector would be cheaper probably even with the cost of shipping.
