I will take you around 4-5 most popular flea markets in Porvoo by my car as situated little bit outskirts in Tarmola area. You can easily find some Finnish design things like Marimekko, IIttala, Arabia in those favourite treasure hunting spots of mine.
Kuka on Tiinakaisa - tietoja Doerista
Flea markets and bric-brac places are my big passions. I consider myself as a flea market pro as started the hobby already at the age of 8 when hanging with my great grandfather EinoMatias who was a real collector. Where ever Im travelling around the world , Im always checking the local treasure markets :)
Some places accept credit cards but good to have some cash and rather smaller bills with you.