I managed to get a brand new one on clearance from Target for $50

. I was in there looking for gifts for my children who are (6years) 2 days apart and we were having friends over so it got alot of use.
I have also been able to take it to friends houses for their kids birthdays/gatherings etc and it only takes 5 mins to set up (about 30 seconds to inflate once layed out etc) and 5 mins to pack away. It is not huge but it isnt too small. It fits around 8 kids on it.
I wouldnt pay $300 like it was before on clearance though!