For both prostitution and patronizing, it is a crime to merely offer to buy or sell sex. These charges are Class B misdemeanors for the first offense, Class A misdemeanors if it is a second or third offense, and a state jail felony if you have been convicted three or more times. Promoting prostitution is a Class A misdemeanor. Aggravated promotion is third degree felony. Compelling prostitution is either a second degree felony (if the person is over 18) and a first degree felony (if the person is under 18).
In addition, it is a separate, more serious crime to solicit a minor for sex. If you offer to pay a person who is between 14 and 18 years of age, it is a third degree felony. If the person is younger than 14, it is a second degree felony.