I assume you want to find full boxes of period-correct ammunition for display purposes? There are a number of antique ammunition dealers who probably can help you. Just Google. You might also check on GunBroker. High condition full boxes suitable for display will not be cheap. A high condition and unopened WWI box of half-moon clipped military .45 ACP will probably set you back close to a grand, it is very difficult to find. More easily found and much cheaper is a 20-round unopened box of WWI GI .45 ACP for the M1911 pistol. A common good condition full and sealed box of .32 RF should be much less, maybe several hundred, depending on box condition, age, and manufacturer. Not to say that an unusual older box couldn't go much higher.