Before the crash of 2008, the PIAT launchers were selling for around $3500, and nice bombs easily fetched $400. After the crash, I picked up a launcher for $1900, and have never paid more than $150 for the bombs. Prices have seemed toclimb back up to almost where they were in 08, so I would suggest you are looking at around $3K for the launcher, and $250-$400 for the bombs. Of course, condition is key to all these prices. If the launcher has it's canvas and slings, then you could be a little above the 3K. If it does not, then maybe a little lower. Same for the bombs. A minty bomb with it's container will be higher than a repainted trainer missing it's nose cap.
If you have a look on collectors source, you will kind of get an idea of some of the price variations.