I have a few questions about strut bars for a 97 altima, Are they easy to install, do i neeed special tools and how much would one cost

There are two kinds, a rear strut bar and a front strut bar. I'm not sure about the application for that car specifically, but in general they are pretty simple to install, as they are attached by two bolt on each strut.

they are by far the easiest mod that isn't cosmetic. take off the three bolts on your struts inside the engine bay. usually rigt over the wheel well. put the bracket over the three screw and reapply them. in the back the same three screw design is there but it's probaly covered by the trunk fabric. you'll have cut a lil square of fabric out so the bar can fit. i'd only get the front STB cuz there's not much pont in making the rear end rigid in a FWD car. get it if you want, but the rear swaybar from stillen or addco is the real way to stabilize the back of the car.