To get back to the original question, there's a spectrum of prices on these parts depending on the eagerness of either buyer or seller. I can tell you what I've paid from my experience but that may not reflect today's reality (I've been able to score some incredible deals). The tappet bodies were gold from TCM a few years back when I needed some but I ran across them dirt cheap on eBay, both new and yellow tagged from Rick Roman's. Same thing with the other parts. I've been able to pick up the lifters themselves ready to install less than the price of having my old ones flow tested and installed. So, here's what I know:
> Camshaft (1) 626608
$360 (if a buyer is really lucky) and up on eBay, and then up to $900 for a new one. The cheapest one on eBay right now is $599 with a "buy it now" of $999.
> Lifters (8) P/N 530851
That part number is for the tappet bodies. Lifters are the things that go inside them and are a separate part number.
Here's a recent
eBay listing [
ebay.com], which was a set of twelve of them for a O-300. Only eight would be needed for an O-200, so 2/3 of that price is $360. However, that's ridiculously cheap and I bet the buyer picked them up to stick on the shelf until needed just because of the price. New ones retail for $318.... each. When they're pitted from corrosion and can't be reconditioned, you're stuck. I managed to buy a set of new ones with lifters installed off of eBay for dirt cheap and I'm hanging on to them. I was given a price of $210 for a reconditioned used one once. Again, that's "each".
> Rocker arms(5) 1 intake and 4 exhaust.
I had one rocker arm red tagged last year and was able to buy a replacement ready to install from Rick Romans for $60 (rebushing and inspection for my old ones was $24 each, so $60 seemed reasonable).