pound-foolish
/ˌpaʊn(d)ˈfuːlɪʃ/adjective
Foolish in dealing with large sums of money, especially while taking care over small ones. Frequently in penny-wise (and) pound-foolish.
Origin
Late 16th century; earliest use found in Francis Meres (?1566–1647), writer and translator. From pound + foolish.