At 73 years old, Harrison Ford stands to make at least $34 million for reprising the role of Han Solo. Ford was paid $25 million up front, and given a 0.5% share of the movie's earnings, meaning when the film hits $2 billion worldwide (it made over $500 million on its opening weekend), he'll get another $9 million. Meanwhile, Carrie Fisher only got $1.5 million to bring back General Organa.
Even that's a considerable bit more than what the film's two new stars, Daisy Ridley and John Boyega, received; they each only got $450,000 (but do receive a share of the profits once it earns $1 billion globally). If you're keeping track, that means Ford is making 56 times what they are, and 17 times what Carrie Fisher got.
Han Solo is a pretty big deal, but that's still pretty ridiculous. I guess it's a little bit of back-pay for the measly $10,000 he received for the original film.