Given the following context:  Ben Mockridge is a young man proud of his $4 handgun and enamored of "cowboyin'". He asks Frank Culpepper if he can join his cattle drive to Fort Lewis, Colorado. Culpepper (a reformed gunslinger) reluctantly agrees and sends Ben to the cook to be his "little Mary". Ben quickly discovers that the adults have little interest in young'ns, and no interest in "showing him the ropes". Culpepper nevertheless assigns Ben tasks the greenhorn handles poorly—or simply fails at—repeatedly causing serious trouble. After rustlers stampede the herd, Culpepper tracks them to a box canyon. When the rustlers' leader demands 50 cents a head for having rounded up and taken care of the cattle, Culpepper will have none of it. He and his hands kill the rustlers, not hesitating to gun down disarmed men, or repeatedly shoot anyone still moving. They lose four of their own in the fight. Culpepper directs Ben to a cantina a day's ride off, to find Russ Caldwell. Before he can reach the cantina, Ben is accosted by trappers who take his horse and gun. Once Ben finds Caldwell, he and three of his buddies agree to join the drive. When they cross the trappers' path, there is no parlaying—they immediately kill the trappers and take their possessions. When Ben stands night watch, he's unprepared for a one-eyed man trying to steal the horses. Instead of immediately shooting him, Ben lets the man distract him with his talk, and is overcome by another thief. Culpepper is outraged at Ben's stupidity.  answer the following question:  What is it that Frank Culpepper will have none of and, instead, decide to kill the rustlers?
Answer:
rustlers' leader demands 50 cents a head