You can buy 1000 grams of peaches for 5 yuan in a fruit shop, and B fruit shop sells the same variety of peaches for 3 yuan per 500 grams, buy 1000 grams and get 1000 grams free. To buy 800 grams of peaches, which fruit shop is more cost-effective?
在甲水果店5元钱可以买1000克桃，乙水果店卖同样品种的桃，每500克3元，买1000克送1000克．要买800克桃，到哪家水果店去买比较合算？
<result>800</result>