So a couple months ago I asked about bouncy castles here and so I ended up getting one. I can report back that it's been money well spent (it was $420 on Amazon) as we've used it 6 times in about a month and it hasn't gotten boring yet. Setup and teardown has been a lot easier than I expected - about 5 mins to get it up and running and about 10-15 mins to pack it up (need to wait for it to deflate). Having kids over has never been easier.
I found the sweet spot for features/price was around $400-450 - beyond that you're just getting stuff that's has princesses or knights on it (or similar) and below that and you're missing some useful features (slides not big enough, no climbing wall, no obstacle course type things).
I figure if I can get 20-25 uses out of it in the next 2 years it'll be worth it (rentals cost $250-450 a pop).
