Dime's Worth Meaning

(idiomatic) An insignificant amount

Example:   Why is he here? Nothing will change. At best, he'll make a dime's worth of difference.
1941, L.H. Robbins[1], The New York Times:
  But why, he asks, should a similarly rapt and adoring crowd bank up before a lighted wall niche containing nothing but a dime's worth of daffodils and a couple of sprays of forsythia in a blue dish?