Comes as standard without a roof-covering???
And not treated?
And needs a concrete base anyway?
No way I'd pay that money for 2m² + verandah & a swing.
I'm sure there are thousands of plans available in various corners of the internet. When I built my children their playhouse, I didn't bother - just built it straight up from the ground. All done in a day (with the help of MrsCR & the two eldest). That was 25 years ago; it subsequently moved house (and country) with us, graduated to being a chicken shed after a while, and is currently "flat-packed" at the back of the garden waiting to return to service. I reckon we didn't spend more than a couple of hundred on it.