an amount of weed sold by ten dollars

the thing that you don’t have when you’re phones percentage is over 20

A very beautiful and flawless woman.

Refers to a beautiful girl who is a "10" on a scale.
Dime = 10 cents

Dropping "a dime", refers to turning someone in for a crime. "A dime" being what it used to cost to make a phone call on a pay phone.

A unit worth 10 cents in the United State currency system.

A "dime," being worth ten cents, is a reference to the 1979 movie "10" with Dudley Moore and Bo Derek.
Calling someone a dime is saying they're a "10," or perfect.