A.D.
I would think renting all that stuff would be costly. For my children's last birthday. We bought a waterslide at walmart for 2 or 3 hundred bucks, got a little pool for 10 bucks. Made water balloons and face painting. I made their cakes, put up a chocalate fountian and snack. Set everything up food and seating wise in the garage, we also put several camping chairs out were the slide was so the partents that wanted to watch the kids closer could. We had one of the teanagers that could draw do the face painting. Did a water balloon toss. The kids were wet all day and had a blast, all for under 300.
My girlfriend went with the same idea but she bought a large pool at sams and set up a water slide. Got a tent, tarp thingy form sams for about 50 she to spent around 300 for her childs birthday.
The slide we got should last us about 4 or 5 summer's so we thought it was a good investment.