Arbitrage noun the simultaneous buying and selling of securities, currency, or commodities in different markets or in derivative forms in order to take advantage of differing prices for the same asset. verb buy and sell assets using arbitrage. Trader Joe's Tote Bags, original purchase price bought for $2.99 now reselling for upwards of $10K Ebay listed for $49K!! supply and demand - the new scarcity + culture = insane markups.