Mont. Code Ann. § 27-1-314

The detriment caused by the breach of an agreement to convey an estate in real property is considered to be the price paid and the expenses properly incurred in examining the title and preparing the necessary papers, with interest thereon. If the breach was in bad faith and the agreed price was less than the value of the estate, the detriment is also considered to include the difference between the agreed price and the value of the estate at the time of the breach and the expenses properly incurred in preparing to enter upon the land.