The original was built for Wendy Darling in J. M. Barrie's play, Peter Pan, or The Boy Who Wouldn't Grow Up.
It was inspired by the wash-house behind Barrie's childhood home in Kirriemuir[1] and first appeared in story form in The Little White Bird in which fairies build a house around Mamie Mannering—the prototype for Wendy—so protecting her from the cold.
It was constructed like a tent so that it could be erected quickly during a song which Wendy starts with: I wish I had a darling houseThe littlest ever seen,With funny little red wallsAnd roof of mossy green.
[1] In South Africa, Wendy houses are a form of accommodation for live-in domestic workers and is a wooden structure on the employer's property.
A few online companies offer rustic, inflatable, or corrugated iron varieties with corporate manufactured designs utilizing plastic, purchased from big-box stores and requiring assembly from brands such as Fisher-Price, Little Tikes, Playskool and Mattel for the suburban backyard market particularly North America and Europe.