There are four properties at Bonnet Creek -- three hotels and a large timeshare.
Most of the time, when people talk about "Bonnet Creek" they are talking about the Wyndham Bonnet Creek timeshare, which consists of six timeshare condo towers built around a large lake. The timeshares are 1-4 bedroom condos with full kitchens, washer and dryer, dishware and cookware, etc. They do not have maid service, and as others have posted, there is no "resort fee" or parking fee for timeshare guests. There is a fee for the shuttle service to Disney parks and Downtown Disney.
At one end of the lake, there is also the Wyndham Grand Hotel. The timeshare and hotel share amenities, so staying at either you would have access to all six of the pools, lazy rivers, activities, restaurants, spa, etc.
The Wyndham Grand is booked through Wyndham directly, and you can also book timeshares through them...but you'll pay a much higher price than if you rent a timeshare through an owner or owner's broker.
The vast majority of the Bonnet Creek postings you read here on the DIS are referring to timeshare rentals booked through an owner or owner's broker.
The WBC timeshares can be booked for any number of nights, but bookings are limited to 3, 4, and 7 night stays during peak season. That's true either directly from Wyndham or through an owner. Single night stays are the hardest to get, but sometimes you get lucky.
In the same general area is the other complex, consisting of Hilton Bonnet Creek and the Waldorf Astoria. Those are both nice hotels, and they share all amenities including the WA's golf course.
