I recommend a trip to Hilo if you are on the big Island. It is about 90 minutes from Kona or Waikoloa if you take the direct route or 120 minutes if you go around the island. Going direct saves you time while going around the island offers you opportunities to stop and see some beautiful gardens.
But when you get to Hilo (the second largest Hawaiian city), you will find a village like town with lots of small shops. I highlight a bakery, a chocolate shop (cocoa grown on the big island), and locally grown Hawaiian coffee. If the views of the mountains or the gardens isn’t reason, then I suggest Hilo for its treats.