There is always a gap between tracker and traffic source data

I use propeller for traffic and binom for tracker, but the data from propeller and tracker are different, and the prices are also very different. For example, today I use propeller and get 9,934 clicks while binom gets 7,754 clicks. Propeller cost 15.7 while binom costs 13.37. Other similar data also have big differences. I don't know what the problem