Re: Cost: Custom action vs. worked Remmy??
+1 on what randy said.
if you don't want fancy stuff like a side bolt release, big ass bolt knob, fluted bolt, sako/m16 style extractor, etc a trued factory action may be good enough and bit cheaper. if you want all those things, or any of them really, then a custom action is going to have a cost advantage.
edit: one more thing, a factory action may or may not come with a trigger you are going to use. a custom will not come with a trigger at all. a factory action may come with a j lock and you will probably want to swap that out. a custom action will come with a firing pin that is good to go.