There should be a "you don't have enought np to buy that" or something because i missed around 5 codestones
Or...you could just make sure you have enough out when you start running it. It tells you how much you have on hand when you log in, so...if you don't think it's enough for how long you're running it, go get more out.
Yeahalways keep like 50k+ on hand when you go to use the igloo aber, that way you wont run into that problem.