There are as many options for kids’ playhouses as there are for any adult habitation – there may be more, since the specifications aren’t as strict. Like a regular house, budget and available space are the main limiting factors; other than those things, imagination has pretty free rein.
If you query online with two words – ‘kids’ and ‘playhouse’ – you will find an exhaustive roster of possibilities, so narrow your search a little beforehand. You need to decide how much space you can allot for the playhouse, where it will be located and the approximate size of its users (big difference in ones suitable for toddlers and ones meant for older kids.)
If you have the time, the inclination and the know-how to build it yourself, you can probably save money, and you’ll have the immense satisfaction of designing something unique (if you have some talent in architectural design). For better or for worse, the majority of parents who want a playhouse for the kids find it much easier and faster to buy one of the huge range of prefab playhouses.
Obviously, if you have more than one child and/or both girl(s) and boy(s), there will have to be some compromise. The same is true of different ages, as growing kids develop new interests frequently, sometimes overnight. The best course is to get everyone who will be using the playhouse involved in the planning stages, and try to get a consensus on the general layout.
Once you have a basic idea of size and style, there are (literally) countless sites advertising all sorts of options, from schoolhouse to mansion, from pirate’s dens to prince’s castle. Prices range from a couple hundred pounds to a couple thousand but the majority are in the middle somewhere.
Note that the prefab models are usually made of either wood or plastic; wood is more durable as a rule, and easier to work with if you want to make changes or additions. There is certainly no lack of delightful possibilities, and your kids will undoubtedly come up with some ideas of their own. After all, that’s what a playhouse should be – a realm of imagination for kids to rule.