There's a little side quest in Macalania Forest (North and Central) which involved butterflies. Touch a multi-colored butterfly and a timer starts to countdown. You have to catch 7 butterflies in the time limit, but beware there are also red ones. If you touch a red one you will get an encounter.

In order to get a price you DON'T may touch a red butterfly.

1. First Time in the Woods: MP Sphere x1, Ether x1
2. After defeating Spherimorph, but before getting Airship: Megalixer x2, Elixer x2
3. After getting Airship: Teleport Sphere x1, Saturn Sigil