as far as the PPUs, it depends on the PPU as far as its worth.
The ones that can be salvaged and used in the NES RGB mod are worth more because of the number of people that want an NES with RGB. Those PPUs are the ones used in PlayChoice10s, Vs. Duck Hunt (some of them), and Vs. Tennis I believe.
The SMB PPU is roughly worth about 50$ because it is sought after by arcade collectors for nostalgia and it is fairly difficult to find.
However, on the other side, the Hogans Alley PPU is so common that oftentimes you can pick up the PPU and 6 EPROMs for 20$ or a bit more.
So yeah, I can see them being worth 200$, and that is the reason why I won't even consider purchasing a Playchoice10 without the PPU because you will spend more money trying to find the blasted chip than the entire system.