I discovered several years ago that when washing your towels, do not add any fabric softener to the washer, nor any dryer sheets to the dryer. By eliminating that step, not only do you save money, but your towels will be more absorbent, and thus, work better at getting you dry!
Another thing our family does is that we each have our own towels. And we use them 3-4 days before we wash them. This can add to a lot of savings if you are used to doing them every day.