You can buy children's used clothes for reasonable price. You can also sell children stuff.
Kid's Recycle (キッズリサイクル）chu chu 10:00~16:00
It has clothes only. There are many popular brand clothes.
Close: Saturday , second and fourth Sunday
Kid's Mart 10:00~18:00
It has not only clothes, but also toys, stroller, shoes, bed..etc.
There are lot of adults and children's clothes, toys ,bags, furniture, books, CD....etc.
OtherIbaraki's Recycle shop