buy是最为普遍的用词，purchase有时在较为官式的场合出现，比较上来得文化意味较重，而且似乎经过“深思熟虑”才决定的。buy可以替换purchase，但反之不行。buy和purchase虽然都可作名词，但若是指一项“购入”则多用purchase。
purchase的用法例句1.Purchase tax was not payable on goods for export.
出口商品不需要交购买税。
2.Investors can borrow an amount equal to the propertys purchase price.
投资者可以获得与房产购买价格相等的借款额。
3.When her deal is done， the client emerges with her purchase.
交易完成后，委托人会出现并将她购买的东西交给她。
buy的用法例句1.Its a good buy at that price.
这是一笔价钱合算的买卖。
2.They bought peace with their freedom.
他们牺牲自由换取和平。
3.Money cant buy happiness.
金钱买不来幸福。
