Newb question: making stamps?

[JOS87]

Very early in the game and was hoping for a little help. I don't really want to consult a guide, but I was wondering what is the main way to make stamps early in the game? Is it by just completing achievements and reaping the rewards from them or do you sell the frogs you catch? Thanks!

[Melancholy Mechana]

Achievement goals and selling the alternate coloured crabs and frogs you catch worked for me.

[JOS87]

Originally posted by Melancholy Mechana:

Achievement goals and selling the alternate coloured crabs and frogs you catch worked for me.

I guess I haven't explored enough to figure out where to sell the fish. What NPCs buy them?

[Melancholy Mechana]

Starting from the Ego Clinic, click left twice. You'll be parked in front of Siger, you can sell your catch to him. From there click left then north, this is the elevator to the department store. Stores are on the second floor and Moriwaki's Customs on the third.