I got a set similar to the ones below. My 7 year old and 4 year old jump on it and it has held up great. I'm scared to jump, but holds my 175lbs just fine....

Install was super easy, and if we need to escape, just push up and the whole things pops off the window well.

http://www.homedepot.com/p/Shape-Pro...8UNV/202532141