Outdoor Habitats For Cats

Outdoor habitats for cats, allows them to enjoy the outdoors while keeping them safe.  I think these are a great idea, I would love to have one.  Only downside, is there price is high, I guess they are targeted to people with lots of money.  I need to do more research and if there are none available for a fair and reasonable cost, perhaps I can make one that is, market and sell it!