Advance Auto Parts sells a boot or cover for less than $4. Don't use it unless you are removing the Rack. It is very flexible but impossible to replace with the Rack in the car.
The more expensive boots are rigid and can be installed without breaking or bending hydraulic lines.
I broke the return line when trying to install the flimsy boot. I ended up buying the better boot along with a new return line. I spent a whole day redoing it.
Take my advise and buy the stiffer boot.