Owning a trampoline can also be an issue with your homeowner's insurance. Some policies exclude any injuries on the trampoline from coverage, and some policies will even deny or cancel coverage if you have a trampoline. It would be worth a phone call before buying one.
1st and 2nd Kid have a 36" Mini Trampoline they were given as a gift a few years ago and they love it. I enjoy that that
A) its small size makes it portable so it can be used indoors and out
B) they really can't get that much air jumping on it and only 1 person can jump at a time
C) On a rain day if you turn on some upbeat music they can really wear themselves out jumping