That puts the frameset in an odd price zone. For that price you might as well just pony up another 150 and buy a used complete Langster off fleabay since they go for $400 all day long. It would make a lot more sense than spending $250, which I would agree the frameset is probably worth, then spending much more on wheels, crank/BB, saddle/post, bars, brakes, etc.

I'd try to get it for cheap as possible since you have to come with the other components. Start low and see what price you both settle at.