The dollar amount for felony theft can vary state-to-state. Any theft that exceeds the dollar amount that the law sets as a threshhold would be considered a felony theft.
If you are charged in court with a felony offense, the judge will hold a bond hearing to see if you are elgible for release on bond. If you are, he will set a monetary amount for the bond (e.g.:...
Typically it is the monetary amount of what is stolen. In many states, the dividing line is above or under $500-this makes theft grand theft or petty theft.