I really need to put in a new gas tank and trunk floor is pretty bad. Ive ordered a new gas tank and new trunk floor pan. How much do you think these are going to cost go get installed?

 

labor on the tank should only be an hour, assuming your strap mounts are not rotted like the rest of the trunk, and your sending unit isn't going to turn to dust when you remove it.
As far as the trunk pan, it all depends on who you have do it, and how much they actually enjoy doing that kind of repair. If they roll their eyes at it, or are too eager to get your money, those are sure signs to take it elsewhere. Now's a good time to justify getting that welder you may have always wanted.