This was a nice find to educate myself about the devastation of tsunamis on this island. The price of admission was $8. The displays are well done, but require a lot of reading. They have an interesting video as well.
This little museum (in a former bank) on the main street in Hilo is well worth a visit. You'll learn that a tsunami is much more than a "big wave" and how tsunamis have affected Hawaii and other areas. Very moving.