I want to rip out all of my carpet and sidewalls inside and put a spray in bedliner on it all. What all must be done before I am ready to spray it? Is it going to be a really hard process? How much do you think it will cost for materials? I got two estimates today and they told me almost $800 to do my inside and that is way too much money for me to spend so I want to do it myself if at all possible.