What are the phrases for "giving up something big for something small", emphasizing that it is not a smart move? E.g., in one TV episode, the main character thinks gathering golf balls from ponds in a golf court is a lucrative business, so he gives up his normal job to do so.
EDIT: @Merk, the example illustrates what I'm asking for. The "giving up something big" is not, it is somewhat directly translated from Chinese idiom, "throw away a melon to pick up a sesame", emphasizing silly choices. I think a close phrase in English is, "give up a dollar for a dime", if there is such a saying at all.