Hi there and welcome to RB! $4 a pound for LR is a great deal I think. I pay $5.99 a pound at my LFS which I thought was a good price.
Personally I think you are doing the right thing going with FOWLR to start. This is the way I have started to get better acquainted with the hobby. Now that I am I have started saving for a nice big reef tank which takes tons of money and fancy equipment, time etc...
After you add your water and get the salinity right then add the rock on the bottom of the tank right on the glass. Do min. 1 pound per gallon, do it all at once so it can cure together at the same time. Otherwise if you buy more later you will have to cure it in a seperate tank. If you don't cure it in a sperate tank you will run the risk of your main tank having to recycle, which could in turn kill the fish etc... Next add the sand, I know it will collect all over your rock, use a powerhead to blow it off the rock and then arrange the sand how you like it. You add the sand last so that the rock has a stable base in the sand to sit and not tip over etc...
Now it's just time to let the tank cycle, takes weeks, sometimes a month or so. BE PATIENT!
Some important tips, get a good test kit, I use API and have no problems with it, but just as important get a Refractometer, this tells you your salinity level, very important and is SO accurate. Don't let your LFS tell you it's ok to use a hydrometer, they are so inaccurate, I learned the hard way.
Good luck and keep us updated.