The bad news: removing them to save and reuse is difficult, because the clips are inside the door and, if I remember correctly, require the removal of the inside door panel and the window glass.
The good news: removing them to replace is simple; just pry them up with something that won't mar the paint (I used a plastic trim removal pry tool). The inside clips will snap off and the whole thing will come off from the outside. The new ones snap in easily without removing any other components. Makes a big difference in appearance and interior noise, especially if your old ones are getting worn.
I priced mine online from somewhere, then took the printout to my local dealer and they matched the price. Saved me about $120 on all four.