The US Postal Service is seeking approval for a price increase on US stamps from 44 cents to 46 cents. If approved, the stamps would go up in price effective January 2nd, 2011. As an approval is likely, stamp arbitrage may be possible by buying stamps for $0.44 and selling for $0.46 after next January 2nd. However, because of the time difference, real return may be closer to zero. Nevertheless, it might work if one could buy at old price and sell at new price soon after (quick 5% return). Although the market for postage stamps doesn’t seem to be all that liquid, it seems completely legal to sell stamps at higher price than the US post office. In fact, third party sellers such as grocery stores or other retail stores often add a small charge to the price for a book of stamps.