The department is authorized to acquire by purchase, gift, or condemnation and to pay just compensation for any property rights in outdoor advertising signs, displays, and devices which were lawfully erected in compliance with the applicable laws in effect at the time of erection but which do not conform to this part or which fail to comply with this part due to changed conditions beyond the control of the sign owner. The department shall be limited to an expenditure of $5 million for the state's portion of just compensation. The department shall be prohibited from paying more than 25 percent of any award for just compensation.