Looking at bouncy castles online this one at Smyths Toys looks like really great value. You can get small bouncy castles for around £50 or so online, but this is a pretty big one, and the air blower is already included, as is home delivery and all with £20 off making it £79.99.
If you urgently want one you can collect it in stores, or it is in stock online for home delivery. All the dimensions are on the website so that you can check that it will fit in your garden. Side netting and ground pegs are included as well as the electric air blower with continuous flow.
The reviews are great for this AirFlow Bouncy Castle, and less than £80 delivered is about the best deal I can find right now. Birthdays? Barbeques? Or just fun in the garden?